BeI2 Lewis Structure, Characteristics:13 Facts You Should Know


This article should learn about BeI2 lewis structure, shape, bond angle, hybridization, and many more detailed fact.

In the BeI2 lewis structure, the shape of the molecule is linear having sp hybridization. The molecule is linearly shaped and two iodine each contain three pairs of lone pairs. As it is a linear molecule so the bond angle of I-Be-I is 1800.

BeI2 is a halogenated salt of alkaline earth metal. Be is alkaline earth metal and can form a strong base with respective anions. The charge over Be is +2 and it is fully satisfied by two iodide anions.

Some important facts about BeI2

BeI2 is solid in its physical state and the color is white. The molecule is hygroscopic which means it can hold the water molecule by absorbing it.

The molecule’s melting point and boiling points are 753 K and 863 K, respectively. In the lattice crystal structure, the BeI2 is orthorhombic.

In presence of elemental Iodine, BeI2 is formed and reacted with Be metal at 500-7000C temperature.

Be + I2 =BeI2

1.    How to draw BeI2 lewis structure?

Before proceeding with the lewis structure drawing we should know lewis structure or lewis dot structure can briefly describe the electrons involved in a molecule for bond formation.

First, we taking consideration of valence electron of Be as well as I. Here Be is a lack of two electrons where two I contain one more electron in their valence shell. Identify the central atom by the electropositivity so here Be is the central atom as Iodine is more electronegative.

The molecule is neutral so the charge over Be and I are fully satisfied by the bond formation so no need to add or remove electrons then three atoms are attached by a single bond only. After that, the lone pairs are assigned to the respective atoms that in over Iodines only.

2.    BeI2 lewis structure shape

In the BeI2 lewis structure, the whole electron density of the molecule lies on the central Be atom.

The structure is linear and Be atom is present at the central position where two iodines are at the terminal site. Lone pairs are present on the Iodines atoms only

3.    BeI2 valence electrons

From the BeI2 lewis structure, it is shown that the linear molecule is attached by a single bond only.

The ground state electronic configuration of Be is 1s22s2 and in the excited state i.e. for Be2+ the electronic configuration will be 1s2, so valence electrons will be two. Again, for I the ground state electronic configuration is [Kr]4d105s25p5 so the valence electrons will be 7 as 5s and 5p are the valence shell for each I.

So, the total number of valence electrons in BeI2 is (7*2)+2 =16

BeI2 Valence Electrons

4.    BeI2 lewis structure formal charge

The formal charge is a hypothetical concept accounting for the same electronegativity for all atoms.

The common formula for calculation of formal charge is, F.C. = Nv – Nl.p. -1/2 Nb.p.

Where Nv is the number of electrons in the valence shell, Nl.p is the number of electrons in the lone pair, and Nb.p  is the total number of electrons that are involved in the bond formation only.

Here in the BeI2 lewis structure, we calculate formal charge separately for Be as well as I.

Formal charge over Be is =2-0-4/2 = 0

Formal charge over I =7-6-2/2 =0

So, the overall molecule is neutral and it is also reflected in the formal charge.

5.      BeI2 lewis structure lone pairs

The lone pairs are those electrons that are not involved in the bond formation.

BeI2 Lone Pairs

From the above BeI2 lewis structure we can see that the lone pairs are only over the I only. So, we add the total number of lone pairs in two I atoms, each I contains 3 pairs of lone pair because the valence electrons for I is 7 and one electron from that participate in bond formation. So, the remaining 6 electrons exist as 3 pairs of lone pairs and Be is lack of lone pair.

So total number of lone pairs in BeI2 is 6+6=12

6.    BeI2 lewis structure octet rule

The octet rule is for every atom is complete its valence shell by accepting or donating a respective number of electrons and trying to gain the nearest noble gas configuration.

In the BeI2 lewis structure, central Be is from the s block and I is from the P block element. Be is an II element whereas Iodine is a VIIA element which means Be has two electrons in its outermost shell and I have & electrons. Be already gain stability due to s orbital filled (s orbital contains maximum electrons) but for I short of one electron to complete its octet, so it shares one electron from Be and completes its octet.

7.    BeI2 lewis structure bond angle

A bond angle is a specific angle between atoms in a particular molecule.

BeI2 Bond Angle

From VSEPR(Valence Shell Electrons Pair Repulsion) theory we can say that in the BeI2 lewis structure the bond angle I-Be-I is 1800 that its shape is linear. There is no violation of that bond angle in this molecule due to the large size of I the lone pair lone pairs repulsion is minimized here. So BeI2 shows an ideal linear shape angle that is 1800.

8.    BeI2 lewis structure resonance

Resonance is a hypothetical concept that can describe the transfer of electron cloud in the same molecule but a different skeleton.

BeI2 Resonating Structure

From the BeI2 lewis structure different skeleton forms, the stable is III as it contains more covalent bonds. After that, we consider the charge distribution of the atom, that if an electronegative atom gets a negative charge or an electropositive atom gets a positive charge is more stable than the reverse.

9.      BeI2 hybridization

Hybridization is also a hypothetical concept to determine the mode of bonding of a covalent molecule by mixing orbitals of two or more atoms to get hybrid orbitals.

The hybridization of any molecule is calculated by the formula

H = 0.5(V+M-C+A), where H= hybridization value, V is the number of valence electrons in the central atom, M = monovalent atoms surrounded, C=no. of cation, A=no. of the anion.

So here in the BeI2 lewis structure, the central Be atom has two valence electrons in its s orbital and two I atoms are present at the terminal position.

So, the hybridization of BeI2 is = ½ (2+2+0+0) =2 (sp)

StructureHybridization valuestate of hybridization of central atom  Bond angle
Linear 2sp /sd / pd       1800
Planner trigonal  3  sp2       1200
Tetrahedral     4sd3/ sp3    109.50
Trigonal bipyramidal5sp3d/dsp3  900 (axial), 1200(equatorial)
Octahedral    6 sp3d2/ d2sp3   900
Pentagonal bipyramidal7sp3d3/d3sp3    900,720

From the above table, it is shown that if the hybridization value is 2 then the mode of hybridization is sp. So BeI2 is sp hybridized. Where S orbital of central Be and P orbital of two Iodine are mixing together to give a new sp hybrid orbital.

10.    BeI2 solubility

Solubility is the phenomenon to which extent a molecule will be soluble in a given solution.

BeI2 reacts with a water molecule to give a new compound. As it is a covalent molecule so its solubility in water is very poor. But it has a greater solubility in methanol and even carbon disulfide also.

11.    Is BeI2 ionic?

According to Fajan’s rule and ionic potential, we can say that no molecule is 100% ionic or covalent.

The size of Be2+ is small so it can easily polarize the larger anion like Iodide. Iodide is larger so it can be easily polarizable by Be2+ ion. So, the molecule possesses an ionic character along with its covalent nature. Be2+ has higher ionic potential as its size is small and charge density is also high so BeI2 shows ionic character.

13.    Is BeI2 polar or nonpolar?

If a molecule has some resultant dipole-moment then it is polar otherwise nonpolar.

BeI2 Dipole Moment

From the above BeI2 lewis structure, we can see that there are two dipole-moment acts opposite to each other. So, the dipole moment of this molecule is zero. So BeI2 is nonpolar. The direction of the dipole-moment always acts from a more electropositive atom toward electronegative an atom.

Here Iodine is more electronegative and Be is electropositive so the dipole-moment acts from Be to I site. As the structure is linear so the direction of the two dipole-moment is opposite and cancels out each other to make the molecule nonpolar.

13.    Is BeI2 acidic or basic?

BeI2 itself is a neutral complex but it when reacts with water the solution turns acidic.

In BeI2 lewis structure, central Be is sp hybridized with vacant 2p orbital and the lone pairs of oxygen in water molecule can be attacked there and it can accept the electron and a strong acid hydrogen Iodide is formed.

BeI2 + 2H2O = Be(OH)2 + 2HI

So, it behaves as acidic in water solution, but in molecular form, there are two electronegative atoms I present, and the electronegativity of two halogens the accessibility of vacant p orbital will be increased.

Conclusion

From the above discussion of the BeI2 lewis structure we can conclude that the molecule has 16 valence electrons, sp hybridized, linear structure along with bond angle 180 degree, and six pairs of lone pair.

Be is not a complete octet but it is still stable due to zero formal charge and has a filled s orbital. Although it is neutral in an aqueous solution it can produce acid and has zero dipole moment making the molecule non-polar.

Biswarup Chandra Dey

Chemistry is not all about reading line by line and memorize, it is a concept to understand in easy way and here I am share with you the concept about chemistry which I learn because knowledge is worth to share it.

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