Biswarup Chandra Dey

Hi......I am Biswarup Chandra Dey, I have completed my Master's in Chemistry from the Central University of Punjab. My area of specialization is Inorganic Chemistry. Chemistry is not all about reading line by line and memorizing, it is a concept to understand in an easy way and here I am sharing with you the concept about chemistry which I learn because knowledge is worth to share it.

Peptide Bond Structure: bond, Resonance, shape, 4 type of structure and detailed fact

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In this article, we discuss what is peptide bond, peptide bond structure, synthesis, and detailed facts.

Before starting with a peptide bond, we first know a peptide bond is nothing but a combination of two or more amino acids. The N terminal of one amino acid gets attached to the C terminal of another amino acid and formed a peptide bond. This peptide bond can form a protein structure.

If amino acid contains any aromatic group then they can form a tertiary protein structure. In short peptide bonds are nothing but a polymer of amino acid linked with amino acids via amide bond with loss of water.

Peptide bond formula

If we consider a peptide bond structure then we can easily find out the peptide bond formula. The formula of the peptide bond is R1-CONH-R2. Where -CONH- is the amide bond linkage and R1 and R2 are the side chain of two different amino acids.

Peptide bond structure

Peptide bond structure is rigid, planner, and trans. It shows a partial double bond character due to the resonance effect between N of amide and O of the carboxyl group.

Here hydrogen from the amide group and O from the carboxyl group lie trans to each other.

Peptide bond structure
Peptide bond structure

Synthesis of Peptide bond

There are five-step to syntheses a peptide bond, they are listed below

  • N-protection of N-terminal Amino acid
  • C-protection of C-terminal Amino acid
  • Activation of -COOH group of N-protected N-terminal Amino acid
  • Amide linkage formation
  • De-protection

N-protection of N-terminal Amino acid (Alanine) using tboc functionality

In peptide bond structure the lone pair over N is attacked on the carbonyl carbon of tboc functionality and get protected Amine group, so it cannot further react with another reagent.

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N-protection by Using tboc Functinal group

C-protection of C-terminal Amino acid (Glycine) by ethanol in presence of acid

In presence of strong acid and ethanol, the acid group is converted into ester, it is a simple esterification reaction. So, this carboxyl group get protected or locked and did not interfare any further reaction.

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C-protection by using Esterification

Activation of -COOH group of N-protected N-terminal Amino acid

 As Carboxylic acid is less reactive due to the presence of the carboxyl group, so it needed to be activated to participate in the desired reaction.

So, we need an activating agent which can activate the carboxylic group.

We use here di-cyclohexyl carbodiimide for activating the carboxylic group by converting it into an amide. Amide has greater reactivity than the carboxylic group.

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Activation of COOH group

The lone pair over O in the carboxylic group attacked the carbon center in DCC and the carboxylic group converted in the amide group.

Amide linkage formation /Peptide bond formation

Now it’s time to make a peptide bond via loss of water between N-protected amino acids and C-protected amino acids.

image 141
Amide bond formation

De-protection

Now its time to de protected the N terminal and C terminal of amino acids to get original peptide bond.

Tboc functionality can be removed by mild basic condition or using TFA/CH2Cl2 and ester part removed by basic condition.

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Deprotection of protected group

The name of the peptide bond is according to the first 3 letters of each amino acid and the first name starts with that amino acid whose N terminal gets protected.

Peptide bond resonance structure

Yes, there is a possible resonating structure in a peptide bond structure.  As the structure of peptide bond is a planner so all the molecules are supposed to be lies in the same plane and resonance occurs within the amide group in between C=O and N atoms which are attached with that C.

image 143
Peptide bond resonating structure

Is peptide bond structure formed during transcription?

In peptide bond structure a transcription factor recognizes the certain region of DNA that controls the genetic code in RNA. DNA protein can form by ZN-fingers and these Zn-fingers contain Cysteine -S donor and histidine-N donor. At last, they form α -helix. Cysteine and histidine are amino acids and they can form peptide bonds in transcription.

The characteristics residue of Zn-fingers is

-(Tyr, Phe)-X-Cys-X2-4-Cys-X3-Phe-X5-Leu-X2-His-X3-5-His-

Where X is variable amino acids. Zn is particularly suitable for binding protein in a particular confirmation according to the Irving-William series and thus makes a stable complex via S and N donors. This is a redox inactive protein so it can avoid the oxidative damage of DNA.

Peptide disulfide bond structure

Many proteins, peptides, and enzymes evolved several defense mechanisms preventing them from denaturation or degradation. Di sulfide bond is one of the protective techniques. Disulfide bond increases the thermodynamic stability of a peptide as well as protein. A disulfide bond can save a peptide bond from high temperature, very acidic or basic pH, and a high concentration of organic solvents by increasing the half-life of the peptide.

Generally, disulfide bonds stabilize the properly folded proteins and destabilized the denaturant.

Mainly disulfide bond can see in those peptides formed from Cysteine amino acid. There are two mechanisms of forming disulfide bonds, one is the chemistry of thiol/sulfide exchange and another is the kinetics and thermodynamics of oxidative folding.

In the 1st step reactivity of Cysteine thiolate will be performed then mixed disulfide is broken by nucleophilic attack from 2nd protein thiolate. As thiol removed as leaving group by the cysteine thiolate.

image 144
Proposed mechanism for intramolecular disulfide bond formation by using Ellman’s reagent, where R is solid support.

Peptide bond structure in protein

There are mainly four types of protein structures

  • Primary – Assembly
  • Secondary- folding
  • Tertiary-packing
  • Quarternary-interaction

Primary structure

The Assembly occurs at the ribosome for the primary structure. Primary structure  involved in dehydration synthesis of proteins and polymerization of amino acids which are attached to tRNA:

NH3+ – {A + B à A-B + H2O}n -COO–

The above process is thermodynamically unfavorable as the change in energy i.e. DE = +10kJ/mol, so the change in Gibb’s free energy will be positive. The primary structure is linear, ordered, and 1 dimensional. It has a special sequence of amino acids which are in some order. By convention, the name of the primary structure is written from the N terminal end to the C terminal end.

For a primary structure, a perfectly linear amino acid polymer is useless as the function of linear amino acid is void and energetically unfavorable.

Secondary structure

In secondary Structure, protein gets folded. The process of folding occurs in the cytosol. The secondary structure of a protein is involved in spatial interaction among amino acids. The secondary structure may or may not involve chaperone proteins but the process is thermodynamically not the favorable value of change in energy is very low.

The structure of a secondary protein is non-linear and 3-dimensional. The stabilization factors of secondary protein are hydrogen bonding, electrostatic force, and van der Waal attraction.

Secondary structure determination

Random coil (Unfolded state)

positive at 212 nm (π->π*)

negative at 195 nm (n->π*)

 b -Sheet

negative at 218 nm (π->π*)

positive at 196 nm (n->π*)

 a-helix

positive (π->π*)perpendicular at 192 nm

negative (π->π*)parallel at 209 nm

negative at 222 nm is redshifted (n->π*)

Tertiary structure

Packing of a protein occurs in the cytosol (~60% bulk water, ~40% water of hydration). Chaperons and membrane proteins promoted the process where solvent and secondary structure of protein gets interacted. Tertiary structure tumbles into molten globule states. This is an essential part. The process is thermodynamically unfavorable as the overall entropy of this reaction decreases due to the hydrophobic effect. Then it is needed for the formation of, the tertiary structure.

The structure of a tertiary protein is non-linear and 3-dimensional like a secondary structure.  The stabilization factor of the tertiary structure is hydrogen bonding, hydrophobic packing even sometime covalent bonds like disulfide bond formation. A globular amino acid polymer is folded and its function is catalytic and it is an energetically favorable Process.

Quarternary Structure

 Interaction occurs in the cytosol, which is very close to other folded and arranged packing proteins so that interaction may be strong enough. The process of interaction in quarternary structure gets promoted by Chaperones, membrane proteins, and cytosolic and extracellular elements. The DE of the process decreases. Here desolvation occurs that results in a reduction of surface area.

Globular protein is an example of a quarternary structure, e.g. hemoglobin.

The quarternary structure is largely involved in the catalytic role. The quarternary structure is also fibrous proteins, e.g. collagen, that plays an important role in structural determination. This way quarternary structure is formed. The quarternary structure is non-linear, 3-dimensional. It is also involved in global, and across distinct amino acid polymers in different amino acid sequences. Hydrogen bonding, covalent bonding, hydrophobic packing, and hydrophilic exposure stabilized the quarternary structure.

FAQ

Why peptide bond is not involved in tertiary structure?

 Actually, tertiary protein structure is formed due to the interaction of the R group of amino acids.

These alkyl group interactions may involve hydrogen bonding, ionic bonding, dipole-dipole interactions, London dispersion forces, van der Waal’s interaction, and some time may be disulfide bonds also. Also, there is sometime hydrophobic interaction that occurs in amino acids which are nonpolar. So, there is no chance of formation of amide linkage or peptide bond formation in tertiary structure.

Why Peptide bond is a partial double bond?

Due to resonance between C=O and C-N of the amide group, there is delocalization of electron and there will be a partial C=N bond formed. This only happens when amino acids form a peptide bond. So, the peptide bond contains a partial double bond.

Why peptide bond is planar?

In a peptide bond, all the carbon atoms of individual amino acids are sp2 hybridized.

So, they are planar and lying in the same plane, It is also evident that it is possible for resonance in peptide bond and resonance occurs only all the atoms are present in the same plane. So, the peptide bond is planar.

Read more about following Structure & Characteristics

ZnO
ZnS
Fe3O4
NaClO2
Lithium
Krypton
Neon
NaHSO4
KMnO4
ZnSO4		NaH2PO4
FeO
Fe2S3
Hyaluronic Acid
Disulfide Bond
Alanine Amino Acid
Glycolic Acid
Heptane
Glycine
Gold		Glutamic Acid
Graphite
Hexanoic Acid

15+ Structural Isomers example: With Detailed Facts

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This article discusses 15+ structural isomers example, their property, classification, and detailed fact.

A structural Isomer is one kind of constitutional isomer. A molecule has the same molecular formula but differs in skeleton structure. Constitutional isomers have different physical properties due to different skeleton frameworks but the same chemical properties, causing their chemical formula same.

structural isomers example

  1. Butane
  2. Pentane
  3. Hexane
  4. 1,2-dibromobenzene
  5. Butene
  6. Pentene
  7. Cyclohexane
  8. Cyclopropane
  9. Cyclobutene
  10. Ether/Alcohol
  11. Aldehyde/ketone
  12. Acid/ester
  13. Keto-enol
  14. Dicarbonyl
  15. Enolate ion
  16. Phenol

Chain Isomer

Chain isomerism occurs in different arrangements of carbon-carbon chains in a molecule. Chain isomerism will show in that molecule having a carbon-carbon single bond only. The physical property of the two, chain isomer will be different but the chemical property is the same.

Butane

The molecular formula  C4H10 has two different structures due to the arrangement of the chain linked with carbon. Former is Butane and the latter is isobutane. Again, their chemical property the same but their physical property is different.

structural isomers example
Structural Isomers Example of Butane

Pentane

The molecular formula C5H12 has three different structures due to the arrangement of single carbon-carbon links. One is n-pentane , and other two are isopentane and neopentane.

Pentane has a higher boiling point due to longer chain size, so the van der Waal attraction force is higher here. For  Neopentane the structure is long as compared to n-pentane. So. the boiling point of neopentane is lower. The boiling point of isopentane lies between n-pentane and neopentane. The boiling point of n-pentane, isopentane, and neopentane are 314,313 and 310 K respectively.

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Structural Isomers Example of Pentane

Hexane

n-Hexane has the highest boiling point among these isomers. N-hexane has long-chain conformation, so the surface area is higher and the van der Waal attraction will be high. Between 2-methyl pentane and 3-methyl pentane, later has a higher boiling point. 2,2-dimethyl butane has the least boiling point as it has the lowest surface area and the force of attraction is very low.

The boiling point of n-hexane, 2methylpentane, 3methylpentane, 2,3-dimethyl butane, and 2,2-dimethyl butane are 342, 333, 336,331, and 323 k respectively.

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Structural Isomers Example of Hexane

Positional Isomer

Molecules have the same formula but differ in the position of the functional group in the carbon skeleton is called positional isomer.

1,2-dibromobenzene

The boiling point of 1,4-bromobenzene is higher than any other isomers. Because this isomer shows molecular symmetry, so in crystallography data is higher.

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Positional Isomerism of 1,2-dibromobenzene

Butene

The molecular formula of these above compounds is C4H8 but the position of a double bond is different. So, they are called positional isomers. The former has less substituted double bond as compared to the next. The stability of a more substituted double bond is high due to the hyperconjugation effect. So, the reactive center will be different for those molecules.

So, the latter has greater stability than the former.

image 80
Positional isomerism of Butene

Pentene

All the above molecules have the same molecular formula that is C5H10 but differs in the position of the double bond and the functional group in the main carbon skeleton. For 1-pentene, 2-pentene, and 3-pentene differ from each other by the position of the double bond. But 2-methylbut-1-ene, 3-methylbut-1-ene, and 2-methylbut-2-ene differ from each other by a double bond as well as the functional group also.

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Positional Isomerism of Pentene

Ring chain isomer

Molecules having the same molecular formula possess a ring chain as well as an open structure called Ring chain isomers.

Cyclohexane

Both molecules have the same molecular formula, C6H12 but one has a cyclic structure and an acyclic structure with a double bond. The former has the most stability as the six-member ring is highly stable, so the former has a higher boiling point. The reactivity of both compounds is different because later has greater reactivity due to the presence of a double bond.

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Ring Chain Isomerism of Cyclohexane

Cyclopropane

The compounds have the same molecular formula C3H6, but one is cyclic and the other is long-chain along with a double bond.

We know a three-member structure contains more angle strain (Brett’s rule) so the cyclopropane has lower stability than Prop-1-ene. So, the boiling point of the latter is more than the former. Prop-1-ene has a terminal double bond so the epoxidation occurs easily.

image 83
Ring Chain Isomerism of Propane

Cyclobutene

For the above molecules, the molecular formula is the same C4H6. But the former is an acyclic structure and an alkyne and the latter is a cyclic alkene. Again, we know a four-member ring has angle strain, so the former is more stable than the latter.

The former has a terminal triple bond, so the reactivity of the former is very high and the boiling point of the former is also very high.

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Ring Chain Isomerism of Cyclobutene

Functional group isomer

Isomers having the same molecular formula but different of the functional group present in it is called functional group isomer. They have different chemical and physical properties.

Functional group isomerism is shown in mainly the alcohol group and ether group. It is a structural isomers examples.

Ether/Alcohol

The molecular formula of these two compounds is the same, C2H6O but in 1st molecule is a primary alcohol group and 2nd compound is ether linkage. The former undergoes nucleophilic substitution reaction only but the latter undergoes nucleophilic substitution as well as elimination reaction. So, the mode of reaction in the two molecules is different. The former has a higher boiling point as there is an ethyl group present as well as it can form H-bond.

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Functional Group isomerism of Ether and Alcohol

Aldehyde/ketone

Both the molecule has the same molecular formula which is C3H6O but one has aldehyde functionality and the other is a ketone.

Due to steric effect and electronic factor aldehyde is more reactive than ketone center. Aldehyde is easily oxidized to form carboxylic acid but ketone can’t be oxidized to break the carbon chain. Due to long-chain aldehyde having a higher boiling point.

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Functional Group Isomerism of Aldehyde and Ketone

Acid/Ester

Both the molecule have the same molecular formula C3H6O2 but 1st one is acid and 2nd one is an ester. The boiling point of acid is higher than ester due to H-bond. The reactivity of both species is different.

Acid forms due to oxidation of alcohol group and ester are formed via oxidation of ketone group. It is a structural isomers examples.

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Functional Group Isomerosm of Acid and Ester

Tautomerism

Tautomerism is a phenomenon in which an interconversion of H atom and double-bonded atom.

Tautomerism occurs in presence of a catalyst, maybe in presence of acid or base catalyst.

Keto-Enol

Both the molecules have the same molecular formula but the left one has ketone functionality and the right one has alcohol functionality along with the double bond.

The carbon-oxygen double bond is stronger than carbon-carbon, due to this reason keto form is always more stable than the enol form.

So, the keto form is less reactive and the boiling point is higher than the enol form. It is a structural isomers examples.

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Keto-Enol Tautomerism

Dicarbonyl

Both the molecule having same molecular formula but the former is dicarbonyl and the latter is keto group along with double bond and -OH group.

So, the physical properties of both compounds are different. For the same reason, keto form is more stable than enol form. Due to the intermolecular H bond, the stability of enol form is higher than the keto form.

image 90
Dicarbonyl Tautomerism

Enolate ion

For enolate ion, keto form is more stable cause the negative charge can undergo resonance with the double bond.

image 91
Enolate ion Tautomerism

Phenol

In the case of phenol, the enol form is the most stable isomer because it is aromatic in nature but its keto form lost its aromaticity.

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Tautomerism of Phenol

7 Steps to Draw NH4+ Lewis Structure,Hybridization (Solved!)

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NH4+ Steps

This article contains the NH4+ lewis structure and its hybridization, shape, bond angle, and detailed explanations. In NH4+ lewis structure, the molecule is sp3 hybridized and has a bond angle of 109.50, so the molecule’s shape is tetrahedral. This structure has no double bond, so the molecule could not show a different resonance structure. There is a shortage of electrons over N in this molecule. So, the positive charge is on N only.

NH4 Lewis Structure

Some facts about NH4+

NH4+ is known as ammonium ion. It is a cationic form of ammonia. The molar mass of ammonium ion is 18.039 g/mol. The ammonium ion is a white and soluble salt. Ammonium ion behaves as a weak acid. The pka value is 9.25. The conjugate base is ammonia.

 The protonation of ammonia synthesizes ammonium ions.

NH4+ lewis structure
Synthesis of Ammonium ion

During the metabolism of animals, ammonium ions produce as a by-product. Ammonium ions behave similarly to alkali metals.

Method of drawing the Lewis structure for NH4+

We always count the total valence electron for every molecule to draw its lewis structure.

In NH4+ lewis structure, there are one N, and four H atoms are present. The central atom is decided by electronegativity, but four H atoms surround one N atom. So, the central atom is N here. All the H atoms make a single bond with the N atom. There is a shortage of electrons over N, so the positive charge of the molecule resides over N only.

Central Atom of NH4+
Octet Rule NH4+
NH4+ Stable octet

The octet of H is completed by forming a single bond with N. Now. We added the valence electrons of N and four H atoms. The ammonium ion is cationic, so the equal number of the electron that is one electron should be removed from this molecule. After making the single bond, there is no lone pair in this molecule. A positive charge is put on N to complete its octet, so, no need to put a double or triple bond here.

NH4+ Lewis Structure
Lewis structure of NH4+
NH4+ Lewis Structure
Electron Dot Structure of NH4+

N has five electrons in its outermost orbital. But here, only four electrons make a four sigma bond with four each H atom. So a positive charge resides on the N atom. Each H atom has one electron, and they are for a single bond with a single electron of the N atom.

NH4+ lewis structure shape

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NH4+ Shape

In NH4+ lewis structure ,four H atoms surround the central N atom. The shape of this molecule is tetrahedral. Four H atoms are present in four corners of the tetrahedral site. 

There are four H atoms present so that the structure can be a square planner, but in square planner geometry, the bond angle of the molecule will be 900. In tetrahedral geometry, the bond angle is 109.50. Increasing the bond angle will decrease repulsion as the N atom is small. The shape of the molecule also indicates the hybridization.

Again, from VSEPR theory, the total electron count for this molecule is (5+4-1) =8, so the molecule’s structure having an electron count of 8 is tetrahedral.

NH4+ valence electron

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NH4+ valence electron

NH4+ lewis structure the distribution of electrons in N is 1s22s22p3, and  H atom is 1s1. So, there are five valence electrons for N and one for H atom. But there is a positive charge in this ammonium ion, which means an electron shortage here. N donates its one electron. The valence electrons of N are four and for four H atoms, the total valence electrons are 4. So total valence electron of ammonium ion is 4+ (1*4) =8.

NH4+ lewis structure formal charge

The following formula can calculate the formal charge of any molecule, 

F.C. = Nv – Nl.p. -1/2 Nb.p.

Nv = number of electrons in the valence shell of the free atom

Nl.p = number of electrons in lone pair

Nb.p = number of electrons involved in the bond formation.

image 60
NH4+ Formal Charge

F.C. of H atom = 1-0-2/2 =0

F.C. of N atom = 5-0-8/2 =1

NH4+ lewis structure as the molecule is ionic species, there will be a formal charge on the molecule equal to the number of positive charges, which is 1.

Generally, the formal charge is equal to its charge for ionic species.

Number of lone pairs in an NH4+ lewis structure

NH4+ lewis structure after the bond formation, if there are pairs of electrons in a single shell, it is considered a lone pair for an individual atom.

Among five valence electrons of N, four of them form a bond with four H atoms in this molecule. H atom contains only one electron. So, there is no chance that H contains lone pair. One electron of N in the valence shell is donated. So, the molecule is lack of lone pairs.

Hybridization of NH4+  

Hybridization is mixing atomic orbitals of similar and different energy to give new hybrid orbitals.

NH4+ lewis structure for hybridization of NH4+, we should count the valence electron of the central atom that is N. In the ground state, the distribution of electron of N is 1s22s22p3. 

In an excited state, it donates one electron from its p orbital, and one electron fromthe s orbital will shift to this vacant p orbital. This way it has four single unpaired electrons in its valence shell. These four unpaired electrons, one from s and one from p orbital under hybridization with four single electrons of four H atoms. 

After mixing these orbitals, a new hybrid orbital sp3 is formed. So, the hybridization of this molecule is sp3.

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Hybridization of NH4+ 
NH4+ Hybridization

The molecule is sp3 hybridized, so the molecule’s structure is tetrahedral. Here only the sigma bond is considered in hybridization.

The central N atom is single-bonded with surrounded by four H atoms only.

Structure    state of hybridization of central atom     Bond angle
Linear         sp /sd / pd    1800
Planner trigonal      sp2       1200
tetrahedral      sd3/ sp3   109.50
Trigonal bipyramidal      sp3d/dsp3   900 (axial), 1200(equatorial)
Octahedral                  sp3d2/ d2sp3    900
pentagonal bipyramidal         sp3d3/d3sp3  900,720

Again, from the table, we can see that the tetrahedral shape molecule will be sp3 hybridized. So, ammonium ion is sp3 hybridized.

NH4+ bond angle

As the central N atom is sp3 hybridized in ammonium ion, the H-N-H bond angle is expected to be 109.50.

image 62
NH4+ Bond Angle

In NH4 lewis structure there is no deviation from this original data cause there are no lone pairs present in this molecule, so there is no chance of lone pair-bond pair repulsion. Besides, N is small in size, and four H atoms are attached with a single bond. Due to the larger bond angle, there is no repulsion.

The VSEPR theory and hybridization table confirm that the bond angle in ammonium ion is 109.50.

NH4+ octet rule

The octet rule is to complete the valence shell by donating or accepting electrons and gaining the nearest noble gas configuration.

NH4+ lewis structure H has one electron. It forms a covalent bond with N by sharing one electron and completing its octet and gaining the electronic configuration as He. N has five electrons in its valence orbital. In ammonium, ion N forms four sigma bonds with four H atoms by sharing one electron. But its octet is not fulfilled. To satisfy its octet, one electron is required. So, a positive charge resides on the N atom only. This way, N and H complete their octet.

NH4+ resonance structure

NH4+ lewis structure contains no π bond. So, we cannot draw the resonance structure its cause there is no chance of shifting the electronic clouds. Even if there is no lone pair of electron density present, we can shift them to draw a resonating structure.

Uses of NH4+ 

  • Ammonium ion maintains the acid-base balance in the human body. The kidney produces ammonium ions to combine with many anions in the body to maintain the acid-base balance.
  • Using ammonium ion, we can synthesize the quaternary ammonium salt which can use in phase transfer catalysts in many organic reactions.
  • Ammonium salt is highly soluble in water, using this fact we can use them as a cleaning agent, surfactant, etc.
  • It is a good Nitrogen source for many plants, so we can use it in soil, but in limiting conditions, the excess will be poisonous.

Compare the N-H length in NH3 and NH4+.

NH4+ , 5+4-1 = 8 (tetrahedral) , NH3 5+3 = 8 (tetrahedral)

Using VSEPR, both NH3 and NH4+ should have a tetrahedral structure. In both cases, the N atoms should be in sp3 hybridized. In NH3, since the hybrid orbital win in which the lone pair is present is of greater “s” character (Bent’s rule), the hybrid orbital of N directed towards the 3 H atoms in NH3 will have lesser “s” character w.r.t. sp2. This is unlike the case of ammonium, where all the hybrid orbitals of N are sp3 hybridized. Thu the N-H length in NH3 will be longer.

Compare the acidic character of NH3 and NH4+.

Ammonia is basic, it has lone pair to be donated in any vacant site of other species, So it behaves like a lewis base.

But in ammonium ion, there will be no lone pair, and it has a positive charge and has an extra proton, so it can easily release this proton and behave like an acid.

Compare the bond angle of NH3, NH4+, and NH2–.

NH4+ > NH3 > NH2–

For ammonium ion there is no lone pair, in ammonia molecule, there is one lone pair and for an for amino ion there are two pairs of lone pair. As the number of lone pairs increases, then the repulsion also increases, and to minimize the repulsion the bond angle decreases.

Frequently Asked Questions

What is the Lewis structure of NH4+ ion?

The Lewis structure of NH4+ (Ammonium ion) consists of a central Nitrogen atom surrounded by four Hydrogen atoms, all connected by single covalent bonds. There are no lone pairs on the Nitrogen atom in this structure. The positive charge comes from the loss of one valence electron by Nitrogen to achieve a stable octet structure.

How does the VSEPR theory apply to the NH4+ Lewis structure?

According to the VSEPR (Valence Shell Electron Pair Repulsion) theory, the shape of a molecule is determined by the repulsion between the electron pairs in its valence shell. For NH4+, all four valence electron pairs are bonded, resulting in a tetrahedral molecular geometry.

What is the formal charge on the NH4+ Lewis structure?

The formal charge on the NH4+ Lewis structure is +1. This is calculated by subtracting the total number of valence electrons in the isolated atoms from the total number of valence electrons in the molecule, considering both bonding and non-bonding electrons.

How does the octet rule apply to the NH4+ Lewis structure?

The octet rule states that atoms tend to form bonds in such a way that each atom has eight electrons in its valence shell, similar to the electron configuration of a noble gas. In the NH4+ Lewis structure, the central Nitrogen atom shares its five valence electrons with four Hydrogen atoms, achieving a stable octet structure.

What is the molecular geometry of the NH4+ Lewis structure?

The molecular geometry of the NH4+ Lewis structure is tetrahedral. This is due to the four Hydrogen atoms symmetrically surrounding the central Nitrogen atom, with bond angles of approximately 109.5 degrees.

What is the electron geometry of the NH4+ Lewis structure?

The electron geometry of the NH4+ Lewis structure is also tetrahedral. This is because electron geometry considers both bonding and non-bonding electron pairs, and in the case of NH4+, all electron pairs are bonding.

How are resonance structures used in the NH4+ Lewis structure?

Resonance structures are not applicable to the NH4+ Lewis structure. Resonance occurs when there are multiple valid ways to place the pi bonds and non-bonding lone pairs of electrons. In NH4+, all bonds are single and there are no lone pairs on the central atom.

What is the bond angle in the NH4+ Lewis structure?

The bond angle in the NH4+ Lewis structure is approximately 109.5 degrees, which is characteristic of a tetrahedral molecular geometry.

Is the NH4+ Lewis structure polar or nonpolar?

The NH4+ Lewis structure is nonpolar. Despite the individual N-H bonds being polar, the molecule as a whole is nonpolar due to its symmetric tetrahedral geometry which causes the dipole moments of the individual bonds to cancel out.

How do you draw the NH4+ Lewis structure?

To draw the NH4+ Lewis structure, start with a central Nitrogen atom and surround it with four Hydrogen atoms. Connect each Hydrogen to the Nitrogen with a single line representing a single covalent bond. Indicate the positive charge of the ion by writing a + sign next to the structure.

Also Read:

NO Lewis Structure: Drawings, Hybridization, Shape, Charges,Pairs and detailed fact

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This article discusses NO lewis structure and its hybridization, shape, bond angle, and detailed explanations.

NO is covalent molecule. The central N atom in NO is sp2 hybridized. The molecule is linear-shaped having a bond angle of 1800. There is a partial triple bond character between N and O. In the NO lewis structure we can see the electron distribution as well as lone pairs.

Some facts about Nitric Oxide

The molecular weight of Nitric Oxide is 30.006 g/mol. The density of N2O is 1.3402 g/L. The melting point and boiling point of Nitrous oxide are 109 K and 121 K respectively.

In the laboratory, Nitric Oxide is prepared by the reduction of Nitric acid with Copper.

8 HNO3 + 3 Cu → 3 Cu(NO3)2 + 4 H2O + 2 NO

This is the most common method to synthesize Nitric Oxide.

NO is a strong filed ligand and it can bind with metal strongly having a low oxidation state. It is very toxic and it can bind with iron in hemoglobin and increase toxicity in the human body which results in death.

Method of drawing the Lewis structure for NO

First, we should count the total number of valance electrons to draw the lewis structure of Nitrous Oxide.

In this structure of Nitrous Oxide, we can see that one N and one O atom is present. Now central atom is decided by the least electronegativity. N is less electronegative than O, So N is the central atom here. O is covalently bonded with N and valence electrons are showing in order to complete their octet. To satisfy the octet after putting all the valence electrons we should use a double bond or triple bond accordingly.

NO lewis structure

One lone pair over N atom and two lone pairs over O atom. There is a single electron on the N atom as N contains five electrons in the valence shell, in order to gain stability the free-electron over N forms a bond with O and there will be a partial triple character observed in this molecule.

NO lewis structure
NO Lewis structure shape

NO valence electron

In Nitric oxide, the N atom is bonded by the O atom. The electronic configuration of N is 1s22s22p3 and the electronic configuration of O is 1s22s22p4. So, taking into consideration the valence shell electron of N is five, among them, two electrons form bond  O and two of them remain as a lone pair and one free electron.

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NO Valence electrons

So, the total number of valence electrons of N2O is 5 + 6 = 11.

NO lewis structure formal charge

The formal charge is calculated using following formula,

F.C. = Nv – Nl.p. -1/2 Nb.p.

Nv = number of electrons in the valence shell of the free atom

Nl.p = number of electrons in lone pair

Nb.p = number of electrons involved in the bond formation.

From resonance the most contributing structure of Nitric Oxide is

F.C. of  N = 5-3-(4/2) = 0

F.C. of O = 6-4-(4/2) = 0

Number of lone pairs in NO lewis structure

The total number of lone pairs is calculated by the sum of an individual atom’s lone pair after bond formation.

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Lone Pairs of NO

So, it is clear after forming a double bond there are a total of three [(1+2)=3] pairs of lone pairs available. Two of them over O and one of them over N.

Hybridization of NO

No is a diatomic molecule having an odd electron. From the data of bond length between N and O which is equal to 1.15 Å, it was thought that hybridization is sp2 as the bond length is in between double and triple bonds. But we can see n cannot fulfill its octet.

If we consider O complete in its octet then hybridization is sp2 according to the formula,

H = 0.5(V+M-C+A) , where H= hybridization value, M = monovalent atoms, C=cation, A=anion.

But this is not the ultimate solution though there is some controversy about the hybridization of Nitric Oxide.

Structure         state of hybridization of central atom           Bond angle
Linear                sp /sd / pd                     1800
Planner trigonal                      sp2                                  1200
Tetrahedral         sd3/ sp3                       109.50
Trigonal bipyramidal       sp3d/dsp3           900 (axial), 1200(equatorial)
Octahedral                 sp3d2/ d2sp3                            900
Pentagonal bipyramidal                sp3d3/d3sp3                               900,720

From this table, it is told that as the bond angle of NO is 1800, so it is sp hybridized.

NO bond angle

The bond angle between N and O is 1800. This data is also confirmed by the hybridization of this molecule. The molecule is sp hybridized so the structure of the molecule is linear.

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NO Bond Angle

The bond length is 1.15 Å, this value is between the double bond and triple bond. So the geometry is linear and the bond angle will be 1800.

NO octet rule

In Nitrous Oxide N cannot fulfill its octet. As there is an odd electron present in this molecule. The outermost electron for N is five as N is the VA element.

So, two of them electrons make the bond with O ( one is sigma and another is π bond) and two electrons reside as lone pair after that there will be one odd electron remaining. In order to gain stability N can form a triple bond with O by donating that odd electron. This way Nitrous oxide completes its octet.

NO resonance structure

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NO resonating Structure

From the above canonical form Structure, II is the most contributing structure as it contains more number of covalent bonds and a negative charge is on the electronegative atom. Structure III is less contributing because unlike charge is over the electronegative atom.

Uses of NO

Nitric Oxide can dilate blood vessels and control high blood pressure.

Frequently asked questions (FAQ)

What are metal nitrosyls?

Metal Nitrosyls are one class of organometallic compounds.

When Nitric Oxide coordinates with Metal then it is called Metal nitrosyls. There Metal nitrosyl can participate in different types of reactions.

What is the correct order of bond strength for No, NO+, NO–?

NO+ > NO > NO–

The Bond order of NO+, NO, N and O– are 3, 2.5, and 2 respectively. The higher the bond order higher will be the bond strength and the lower will be the bond distance.

So, the order of Bond length is just reversed.

Also, please click to know XeO2F2 Lewis Structure and Stearic Acid Structure.

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N2O Lewis Structure: Drawings, Hybridization, Shape, Charges, Pair And Detailed Facts

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This article discusses N2O lewis structure and its hybridization, shape, bond angle, and relevant detailed explanations.

N2O is covalent molecule. The central N atom is sp hybridized and terminal N and O are sp, and sp3 hybridized respectively. Being sp hybridization the geometry of Nitrous Oxide is linear. So, the N-N-O bond angle is 1800.

The central N makes one covalent bond with N and O. The molecule is neutral but in resonance, its show different canonical form, and some of them are charged. To complete its octet central N atom may form a π bond with terminal N and O along with a sigma bond. The lone pairs reside over N as well as O. N-N bond makes zero dipole moment but N-O makes resultant dipole moment. So N2O is a polar molecule.Nitrous Oxide (N2O) is also known as dinitrogen monoxide.

Some facts about Nitrous Oxide

The molecular weight of Nitrous Oxide is 44.013 g/mol. The density of N2O is 1.977 g/L. The melting point and boiling point of Nitrous oxide are 182.29 K and 184.67 K respectively. The most common synthesis process of Nitrous Oxide is the thermal decomposition of dry Ammonium Nitrate (NH4NO3).

Nitrous Oxide is often referred to as laughing gas. It is a colorless, non-flammable gas. The odor of the gas is slightly sweet. It acts as a ligand, coordinates with several metal centers and participates in many organometallics reactions.

Method of drawing the Lewis structure for N2O

Before proceeding with the lewis structure of N2O at first, we should know what lewis structure is. Lewis structure or lewis dot structure is one kind of representation of a molecule showing the valence electrons, especially in the covalent bond.

With the help of the lewis structure, we can easily determine the valence electrons, number of electrons participating in bond formation as well as the formal charge of the molecule.

There are some points, we should kept in mind to draw the lewis structure of a molecule.

  • First, we need to calculate the valence electrons of every individual atom in the molecule and added together.
  • If the molecule is bearing a negative charge then an extra electron equal to the negative charge is added.
  • If the molecule is cationic then an equal number of electrons should be removed from the molecule.
  • Next, we should identify the central atom by its electronegativity, Normally, a competitively more electropositive atom should be the central atom.
  •  Now all the atoms in the molecules are connected via a single bond.
  • Then lone pairs are assigned to the atom, generally lone pairs are assigned to the electropositive atom.

After assigning the lone pairs if the octet of an atom is not completed then a double or triple bond should be drawn in order to complete the octet. If required the lone pairs should be converted to the bond pairs to satisfy the octet.

In Nitrous oxide, the central N atom is surrounded by one N and one O atom. The electronic configuration of N is 1s22s22p3 and the electronic configuration of O is 1s22s22p4. So taking into consideration the valence shell electron of N is five, among them three electrons form bond with terminal N and O and two of them remain as lone pair.

The valence electron of O is six and two of them form bonds with central N and four of them remain as two pairs of lone pair. For the terminal, one electron forms bond with central n and four of them remain as two pairs of lone pairs. So the total number of valence electrons of N2O is (2*5) + 6 = 16.

N2O lewis structure shape

One lone pair over the central N atom and two pairs of lone pairs over terminal N and O respectively. The structure is linear and the electron density is distributed over the molecule.

n2o lewis structure
Lewis structure of N2O

N2O lewis structure formal charge

The formal charge is defined as the charge over a particular molecule assuming that all the atoms have the same electronegativity.

F.C. = Nv – Nl.p. -1/2 Nb.p

From resonance the most contributing structure of nitrous oxide is

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Lewis structure of N2O

So we should calculate the formal charge for individual.

F.C. of terminal N = 5-2-(6/2) = 0

F.C. of central N   = 5-0-(8/2)  = 1

F.C. of terminal O = 6-6-(2/2) = -1

Number of lone pairs in N2O lewis structure

The total number of lone pairs is calculated by the sum of an individual atom’s lone pair. Now we should consider the most stable canonical form according to resonance. The most stable canonical form of Nitrous Oxide is

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Lewis structure of N2O

So, the total number of lone pairs in Nitrous Oxide is (1+3) = 4.

Hybridization of N2O

For calculating hybridization we should consider the most contributing canonical form of Nitrous Oxide. In that form, there will be a triple bond between two N atoms and one single bond between N and O.

It involves the mixing of atomic orbitals having similar energy to form an equal number of mixed orbitals or hybrid orbitals and these hybrid orbitals are so oriented in space that they can overlap with suitable orbitals of the subsequent. If the orbitals are of the same energy is called equivalent hybridization and if the mixed orbitals are of different energy then it is called non- equivalent hybridization.

In the ground state, the electronic configuration of N is [He]2s22p3. We know that the maximum number of electrons occupying in p orbital is 6. To complete the octet N needs 3 more electrons. Again the electronic configuration of O is [He]2s22p4.

To complete octet O need 2 more electrons. So now they will undergo hybridization. For terminal N which makes a triple bond with the central N atom, among them two are π bonds and we should not consider π bond in hybridization. So, In the central N atom, there are two electrons in the s orbital that remain as a lone pair and one electron from the p orbital undergoes hybridization with the central N atom.

So, the hybridization of terminal N atom is sp. For the terminal N atom there is no lone pair, one electron from the p orbital makes a sigma bond with O and one electron from the s orbital makes a sigma bond with terminal N. other electrons make the double and triple bond with terminal n which are not participating in hybridization. So the mode of hybridization of the central N atom is sp.

In terminal O  there are three lone pairs and one bond pair (make sigma bond with central N). So, the hybridization of O is sp3.

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Hybridization of N2O

N2O bond angle

From the hybridization, we know that the central N atom in Nitrous oxide is sp hybridized, so the bond angle of N-N-O is 1800.

Since the terminal O is sp3 hybridized so the shape of the molecule about the terminal O is slightly tilted.

N2O octet rule

According to the octet rule, every atom should complete its valance shell by donating electrons or accepting electrons to gain the nearest noble gas configuration.

Nitrogen is a group of VA elements so it has 5 electrons in its outermost shell and Oxygen is a VIA element so It has 6 electrons in the outermost shell. So, undergoing hybridization there will be new hybrid orbitals form, this way Nitrogen as well as Oxygen complete their octet and gain the nearest noble gas configuration. But there is an excess of the electron over Oxygen so a negative charge resides on Oxygen.

N2O resonance structure

Resonance is a theoretical concept – that introduce to explain the bonding properties of molecules via shifting of the electronic clouds between the atoms in such a way that the main structure of the framework remains unchanged. In fact, it is another bonding model where the actual structure may be represented as the resonance having a hybrid of a number of different canonical forms.

Rules for the most contributing structure

  • The most contributing structure should be one that contains the largest number of covalent bonds.
  • For more than one structure having an equal number of covalent bonds the one in which more electronegative substituents containing the electronegative charge will have a higher contribution, more electropositive substituents containing the positive charge.
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N2O resonating structures

The structure I, II, and III have the highest number of the covalent bond, and hence they will have a higher contribution as compared to that of IV and V. Among I, II, III structure III will have the least contribution since like charges are close to each other. Among structures I and II the former will have a greater contribution since electronegative elements Oxygen contains a negative charge and a positive charge over the lee electronegative atom N.

Uses of N2O

  • It is used rocket motor fuel as an oxidizing agent
  • It is used in the manufacturing of different semiconductors
  • It is used in the medical field as an analgesic and anesthetic and specially used in dentistry
  • It is used as a flavoring ingredient
  • Also used in an anti-anxiety agent.

Frequently asked questions (FAQ)

Which is more polar between N2O and NO2 ?

N2O is linear and NO2 is bent. So the resultant dipole moment in NO2 is higher than N2O, so NO2 is more polar.

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PF3 Lewis Structure: Drawings, Hybridization, Shape, Charges, Pair And Detailed Facts

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This article discusses pf3 lewis structure and its hybridization, shape, bond angle, and relevant detailed explanations.

PF3 is a covalent molecule where P is located at a central position and surrounded by three F atoms. P and F are covalently bonded along with sp3 hybridization. The molecule is in trigonal pyramidal shape but the geometry of the molecule is tetrahedral. F-P-F bond angle is around 970 instead of 109.50.

PF3 is a neutral compound so no charge appears on this compound. Among the five valence electrons of P, only three of them participate in bond-forming and the rest two are non-bonded electrons and appear as lone pairs. PF3 is a polar molecule. So, here we will learn about the pf3 lewis structure and other facts about it in detail.

Some facts about Phosphorus trifluoride

The molar mass of PF3 is 87.98 g/mol, density is 3.91 g/l. The melting point and boiling point of PF3 are 121.7 K and 171.4 K respectively. Its shows a chemical shift value at -34 in 19F NMR. PF3 is normally synthesized via the halogen exchange reaction between phosphorus trichloride and various metal fluorides such as ZnCl2  or Cacl2.

Method of drawing the lewis structure for PF3

Before proceeding with the lewis structure of PF3 at first, we should know what lewis structure is. Lewis structure or lewis dot structure is one kind of representation of a molecule showing the valence electrons, especially in the covalent bond.

There are some points are should keep in mind to drawing the lewis structure of a molecule.

  • First, we need to calculate the valence electrons of every individual atom in the molecule and added together.
  • If the molecule is bearing a negative charge then an extra electron equal to the negative charge is added.
  • If the molecule is cationic then an equal number of electrons should be removed from the molecule.
  • Next, we should identify the central atom by its electronegativity, Normally, a competitively more electropositive atom should be the central atom.
  •  Now all the atoms in the molecules are connected via a single bond.
  • Then lone pairs are assigned to the atom, generally lone pairs are assigned to the electropositive atom.
  • After assigning the lone pairs if the octet of an atom is not completed then a double or triple bond should be drawn in order to complete the octet. If required the lone pairs should be converted to the bond pairs to satisfy the octet.

In this structure of phosphorus trifluoride, we can see one Phosphorus atom is surrounded by three Fluorine atoms. The electronic configuration of Phosphorus is 1s22s22p63s23p3, so taking into consideration the valence electrons of Phosphorus is five among them three are bond pairs and two appear as lone pair, and the electronic configuration of Flourine is 1s22s22p5, so the valence electrons of each fluorine atom are seven and appear as three lone pairs and one bond pair. So, the total number of valence electrons for the PF3 molecule is 5 +  (7*3) =26.

PF3 lewis structure shape

In PF3 molecule electron density lies around the central Phosphorus atom and there are three bond pairs and one lone pair are present.

pf3 lewis structure
PF3 lewis structure

In this case phosphorus trifluoride, the structure is trigonal pyramidal. In trigonal pyramidal structure, one phosphorus atom is present at the central position and three fluorine atoms are present at the three corners.

PF3 lewis structure formal charge

The formal charge is defined as the charge over a particular molecule assuming that all the atoms have the same electronegativity.

F.C. = Nv – Nl.p. -1/2 Nb.p.

Nv = number of electrons in the valence shell of the free atom

Nl.p = number of electrons in lone pair

Nb.p = number of electrons involved in the bond formation.

So the formal charge of the PF3 molecule is 26-(3*6)-6 = 2

Number of lone pairs in PF3 Lewis structure

The total number of lone pairs in Phosphorus Trifluoride is the sum of individual lone pairs of Fluorine atoms and Phosphorus atoms. The number of lone pairs over Phosphorus is one and each Fluorine contains three lone pairs. So, the total lone pairs of phosphorus trifluoride are 1+ (3*3) =10.

Hybridization of PF3

What is Hybridization?

It involves the mixing of atomic orbitals having similar energy to form an equal number of mixed orbitals or hybrid orbitals and these hybrid orbitals are so oriented in space that they can overlap with suitable orbitals of the subsequent. If the orbitals are of the same energy is called equivalent hybridization and if the mixed orbitals are of different energy then it is called non- equivalent hybridization.

                                    

Structure           state of hybridization of central atom             Bond angle
Linear                 sp /sd / pd          1800
Planner trigonal       sp2                   1200
Tetrahedral     sd3/ sp3    109.50
Trigonal bipyramidal   sp3d/dsp3      900 (axial), 1200(equatorial)
Octahedral        sp3d2/ d2sp3               900
Pentagonal bipyramidal   sp3d3/d3sp3        900,720

In the ground state, the electronic configuration of Phosphorus is [Ne]3s23p3. We know the maximum number of electrons occupying in p orbital is 6. So here lack of electrons is 3. Now the electronic configuration of fluorine is [He]2s22p5.

So, to complete the octet of Phosphorus it needs 3 more electrons, and to complete the octet of Fluorine it removes one electron. So, each Fluorine gives one electron to the vacant p orbital of Phosphorus and completed its octet and after taking three electrons even Phosphorus completes its octet too.

So, a stable bond is a formation that happens via the mixing of s and three p orbitals. Phosphorus has two electrons in its 3s orbital as a lone pair and its 3p orbital is filled with six electrons (3px,3py,3pz,  three on its own and three from each fluorine). So here in hybridization one s orbital and 3 p orbital is involved. So, the mode of hybridization is sp3.

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Hybridization of P

In the case of hybridization, we always consider the single bond or sigma bond, not the π bond or multiple bonds. From the above chart, we can easily predict the structure of the PF3 molecule is tetrahedral as its hybridization state is sp3. In the case of structure, we consider the surrounded atoms as well as lone pairs also. But in shape, we consider only surrounded atoms by the central atom. So, the molecule is trigonal pyramidal in shape, not trigonal planner because due to the presence of lone pair the F-P-F bond angle is not even close to 1200. For an ideal tetrahedral molecule, the bond angle is 109.50.

PF3 Bond Angle

From the hybridization table, we can see that for sp3 hybridized molecule bond angle is 109.50. But in the case of the PF3 molecule, the bond angle is nearly 970 (actually 96.30) although the molecule is sp3 hybridized. This abnormality of bond angle can be explained for two reasons. One is lone pair-lone pair repulsion and one is Bent’s rule.

In the PF3 molecule, there will be a lone pair over Phosphorus present in sp3 hybridized orbital and three fluorine have three pairs of lone pair. So here high chance of lone pair- lone pair repulsion. To avoid this repulsion sp3 hybridized lone pair pushes the P-F bond away from it and therefore decreases the F-P-F bond angle. The repulsion is so high that the bond decreases very much and is close to 970.

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PF3 bond angle

PF3 octet rule

According to the octet rule, every atom should complete its valance shell by donating electrons or accepting electrons to gain the nearest noble gas configuration. Phosphorus is a group of VA elements so it has 5 electrons in its outermost shell and Fluorine is a VIIA element so It has 7 electrons in the outermost shell.

So, undergoing hybridization there will be four new hybrid orbitals that will form, this way Phosphorus as well as Fluorine complete their octet and gain the nearest noble gas configuration and form a stable molecule PF3.

PF3 resonance structure

Resonance is a theoretical concept – that introduce to explain the bonding properties of molecules via shifting of the electronic clouds between the atoms in such a way that the main structure of the framework remains unchanged. In fact, it is another bonding model where the actual structure may be represented as the resonance having a hybrid of a number of different canonical forms.

Rules for the most contributing structure

  • The most contributing structure should be one that contains the largest number of covalent bonds.
  • For more than one structure having an equal number of covalent bonds the one in which more electronegative substituents containing the electronegative charge will have a higher contribution, more electropositive substituents containing the positive charge.
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PF3 resonating structure

PF3 polar or nonpolar

For the polarity of a molecule, we should first see the dipole moment of that molecule. From the electropositive atom to the electronegative atom dipole moment works. In this molecule Phosphorus is electropositive and Fluorine is electronegative. So, the dipole moment works from Phosphorus to Fluorine. The molecule is trigonal pyramidal so the shape is not symmetrical. Thus, symmetrical charge distribution does not occur. This molecule has a resultant dipole moment. So PF3 is a polar molecule.

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Dipole moment

Uses of PF3

Having a vacant d orbital of P, PF3 can easily bind with metal with a low oxidation state having a higher number of d electrons. It is a strong π-acceptor ligand due to the presence of three electronegative Fluorine atoms. So, it can participate in many organometallics reactions. So many organometallics reactions can be carried out with the help of PF3.

Frequently asked questions (FAQ)

Why does PH3 have a lesser bond angle than PF3?

Considering the formation of PF3 where three F atoms approach the central p atom along the three axes. When the 3 F atoms come at bonding distance they will suffer steric repulsion due to the lone pair of P as well as F atoms also. Hence the system will go unstable. In order to gain stabilization, the central P atom undergoes sp3 hybridization and the bond angle becomes 970(Bent’s rule).

When the 3 H atoms approach the P center in a similar fashion, it is due to the smaller size of H and larger size of the P atom 3 H atoms will not suffer any steric repulsion. Thus the system is not energies and the px, py, pz orbitals of P are directly involved in the bond formation, and no need for hybridization – thereby accounting for the H-P-H bond angle being around 900.

Is there back bonding possible in PF3 ?

Yes, there is a possibility of back bonding in the PF3 molecule. P has a vacant d orbital and F has 3 pairs of lone pairs. So there will be a high chance of forming dπ-pπ back bonding.

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dπ-pπ back bonding

Also, please click to know about Glycerol Structure.

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