NO3- Lewis Structure & Characteristics: 19 Complete Facts


Nitrate or NO3 is a polyatomic ion with molecular mass 62.0049 g/mol. Let us explore the structure and some important characteristics on NO3 briefly.

NO3 has a trigonal planar structure with bond angle 1200. Nitrogen is attached with three oxygen atoms trough covalent bonds. All these covalent bonds have same length due to resonance. All the compounds of nitrate are water soluble except bismuth oxynitrate.

Let us discuss some relevant topics regarding shape, hybridization, bond angle, solubility of NO3 lewis structure below.

How to draw NO3 lewis structure?

Lewis structures are those structural representation in which nonbonding electrons are shown as the electron dots. Let us follow the steps of drawing the lewis structure.

Determination of valence electrons:  

Both of nitrogen and oxygen are p block element and they have five and six electrons in their valence shell respectively.

Finding out the bonding electrons:

There is one double bond and two sigma bonds are present between nitrogen and oxygen. Therefore (4×2) =8 electrons are involved in bonding.

Finding out the nonbonding electrons:

The two oxygen atoms, attached through single covalent bonds, have six and the oxygen attached through double bond with nitrogen atom has four nonbonding electrons respectively.

no3- lewis structure
NO3 Lewis Structure

NO3 Lewis Structure Resonance

Resonance is the movement of pi electron cloud to all over the molecule for the purpose of stabilization. Let us draw the resonance structures of nitrate ion.

All the resonance structures of NO3 have equal contribution to its hybrid structure. Total three resonance structures are possible for nitrate ion and all of them are equivalent because of the equal N-O bond length.

The resonance structures help to identify the most stable as well as the hybrid structure of any molecule. Formal charge of each of the atom can also be calculated from resonance structures.

NO3 Resonance Structure

NO3 Lewis Structure Shape

Lewis structure shape, defined from VSEPR theory, determines the three-dimensional molecular arrangement of the atoms in a molecule. Let us find out the shape of NO3.

The lewis structure shape of NO3- is trigonal planar. It contains three oxygen and one nitrogen atom which are attached with each other by covalent bonds. NO3- gets this trigonal planar shape due to sp2 hybridization of nitrogen atom.

The shape and geometry of this ion are same because nitrogen has no lone pair in nitrate. If nitrogen has any lone pair, the shape will be deviated from its geometry as the lone pairs will involve in lone pair-bond pair repulsion with the N-O bonds.

NO3 Lewis Structure Formal Charge

Resonance hybrid structure helps to calculate the formal charge of each atom in a molecule. Let us calculate the formal charge of NO3.

The formula of NO3 formal charge calculation is = {Total number of valance electrons – number of electrons remain as nonbonded – (number of electrons involved in bond formation/2).} One positive charge on nitrogen and two negative charges on oxygen atom makes the molecule a negatively charged species.

  • Formal charge of nitrogen = 5 – 0 – (8/2) = +1
  • Formal charge of each of the oxygen attached through single bond with nitrogen = 6 – 6 – (2/2) = -1
  • Formal charge of oxygen attached through double bond with nitrogen = 6 – 4 – (4/2) = 0
  • The formal charge of the whole molecule is = +1-1-1 = 0.

NO3 Lewis Structure Angle

Lewis structure angle, determined from the shape of molecule is formed between two covalent bonds and one atom. Let us explain it in detail.

The lewis structure angle of NO3- is 1200. It is the actual bond angle of any trigonal planar shaped and sp2 hybridized molecule. Like hybridization, bond angle can also be decided from the VSEPR (valence shell electron pair repulsion) theory.

Nitrate ion is showing its actual bond angle according to its shape and hybridization because of the absence of lone pairs on central atom. These lone pairs involve in lone pair-bond pair repulsion and bond angle will be decreased from its actual angle.

NO3 Lewis Structure Octet Rule

Octet rule depicts that any atom should have eight electrons in its valence shell like its nearest noble gas molecule. Let us find out if the atoms in NO3 obey octet rule or not.

All the atoms in NO3 obey octet rule in the following way-

  • Nitrogen has five valence electrons and it shares three more electrons with the three oxygen atoms. Therefore, octet rule is satisfied in case of nitrogen.
  • Each of the two oxygen atoms (having negatively charged) has six electrons in outer most shell and gets two more electrons from nitrogen and octet is filled up.
  • Rest of the oxygen atom (attached with double bond) is also satisfying octet rule because it shares two electrons with nitrogen with nitrogen.

NO3 Lewis Structure Lone Pairs

Lone pairs are considered as those valence electrons which are not exchanged with other atoms through bond formation. Let us discuss on the lone pairs.

Formula of the calculation of lone pairs or nonbonded electron in NO3 = total number of valance electron – number of bonded electrons.

  • Number of nonbonded electrons in nitrogen = 5 – 5 = 0
  • Number of nonbonded electrons in negatively charged oxygen atom = 6 – 0 = 6
  • Number of nonbonded electrons in neutral oxygen = 6 – 2 = 4
  • Therefore, total number of lone pairs in NO3 is = (6×2) + 4 = 16

NO3 Valence Electrons

Valence electrons are defined as those electrons which belong to the outer most shell associated with an atom. Let us count the valence electrons of NO3.

Total number of valence electrons in NO3 is (3×6) + 5 = 23 and it is determined from the summation of the valence electrons of one nitrogen and three oxygen atoms . Being a p block element, nitrogen and oxygen have five and six electrons in their 2s and 2p orbitals respectively.

Nitrogen and oxygen have completely filled 2s orbital (2s2) and 2p orbital which are filled with three electrons in case of nitrogen (2p3) and four electrons in oxygen atom (2p4). These two orbitals are considered as valence shell.

NO3 Hybridization

Concept of mixing two atomic orbitals to generate a new hybrid orbital is called as hybridization. Let us discuss about it.

The hybridization of nitrogen in NO3 is sp2. 2s and 2p orbitals of nitrogen are involved in this hybridization with three oxygen atoms. As nitrogen has no electrons left as nonbonding, all the five electrons are involved in N-O bond formation.

Molecular geometry can only be determined from the orbital hybridization of the molecule. All of the sp2 hybridized atom always show trigonal planar shape in absence of lone pairs.

Is NO3 a solid?

Physical state of any molecule depends upon the nature of the molecule or ion. Let us discuss it.

It cannot be commented on if NO3- is solid, liquid or gas because it is just a polyatomic ion consisting nitrogen and oxygen atoms. To comment on the physical state of NO3, it should be attached with any metal or any atom and then only it can be determined.

Why and How NO3 is not a solid?

NO3 cannot be a solid substance because it is not a compound, a polyatomic ion. Boiling point can only be measured for any compound, not any ion. If it forms any compound, then the physical state of it can be decided. For example, HNO3 is a liquid compound whereas sodium nitrate is a solid substance.

Is NO3 soluble in water?

The solubility depends upon the nature (polar or nonpolar) of solute and solvent molecules.

Most of the NO3 compounds are soluble in water. The compounds containing nitrate ion are polar in most of the times and polar compounds are always soluble in polar solvent like water.

Why and how NO3 are soluble in water?

NO3 compounds are soluble in water because the water molecules form an ionic atmosphere around the polar solute molecules. Positive end of water covers the negative end of solute and the oxygen end of water forms the ionic atmosphere around the positive end of the solute.

For example, the following compounds of NO3- are soluble in water-

  • Sodium nitrate
  • Nitric acid
  • Calcium nitrate

Is NO3 polar or nonpolar?

Polarity or non-polarity depends upon the arrangement of bonds and the electronegativities of the molecule. Let us discuss whether NO3 is polar or nonpolar.

NO3 is polar because it has trigonal shape and all the atoms in it are highly electronegative. There is no cancellation of bond dipole in NO3. Therefore, it contains a permanent dipole moment.

Why and how NO3 is polar?

The polarity of NO3 depends upon its trigonal shape. Let us discuss below.

NO3 is polar because one N-O bond moment cannot be cancelled by another N-O bond. If one bond dipole will be cancelled by another then, the net dipole moment of NO3 will be zero and it will be considered as nonpolar molecule.

Is NO3 an acid or base?

For acidity or basicity of any compound, it should be determined whether it is electron rich or not. Let us find out it.

NO3 is considered as a conjugate base because it is electron rich polyatomic ion. It behaves as lewis base because it can donate the excess electron density to any lewis acid.

Why and how NO3 is a base?

Being a metal nitrate compound like NaNO3, NO3 is formed. Let us focus on it.

NO3 is a base because the excess electron density of it can be donated through the oxygen atom. For nitric acid, NO3 can form a covalent bond with hydrogen, a lewis acid or electron deficient species through oxygen end.

Therefore, the excess electron density of oxygen is shifted towards hydrogen through the new covalent bond between oxygen and hydrogen.

Is NO3 an electrolyte?

Any compound can only be electrolyte if it can be dissociated in two oppositely charged ions in aqueous solution. Let us explain it whether NO3 is electrolyte or not.

NO3 can only be electrolyte if it forms compound with any metal atom or hydrogen. For example, both the sodium nitrate, nitric acid are electrolyte in nature.

Why and how NO3 is not an electrolyte?

NO3 will be an electrolyte and can be dissociated into two opposite ions if it is attached with an atom to form a molecule. Therefore it cannot be commented whether NO3 can be electrolyte or can conduct electricity.

Is NO3 ionic or covalent?

Ionic or covalent character depends upon the presence of ionic or covalent bond. Let us give an overview on it.

NO3 is covalent because nitrogen is attached with the three oxygen atoms through covalent bonds which are formed by the sharing of electrons between the constituent atoms.

Why and How NO3 is a covalent compound?

Sharing of electrons between the atoms makes a molecule a covalent compound. Let us talk about this.

NO3 is covalent due to presence of covalent bonds. These covalent bonds are formed due to sharing of electrons between nitrogen and oxygen. Ionic bonds can only be formed if electron pairs are completely transferred from electropositive to electronegative atom. Therefore, it is not an ionic compound.

Conclusion

Nitrate is a water-soluble covalent compound with significant uses in different fields. It is used as fertilizer in agriculture industry. It also behaves as a good oxidizing agent in different chemical reactions.

Aditi Roy

Hello, I am Aditi Ray, a chemistry SME on this platform. I have completed graduation in Chemistry from the University of Calcutta and post graduation from Techno India University with a specialization in Inorganic Chemistry. I am very happy to be a part of the Lambdageeks family and I would like to explain the subject in a simplistic way. Let's connect through LinkedIn-https://www.linkedin.com/in/aditi-ray-a7a946202

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