Question

If true enter 1, else enter 0. In ${{\left[ {{I}_{8}} \right]}^{2-}}$ ion, two I-I bonds are larger whereas five I-I bonds are smaller.

Answer 1

The class of polyhalogen anions entirely composed of iodine atoms is called polyiodides. ${{\left[ {{I}_{8}} \right]}^{2-}}$ belongs to the octa atomic species of polyiodides class. The structure and bonding of any molecule can be predicted based on hybridization.
Formula used:

Complete step by step answer:
- For determining the type of hybridization of the given structure, the following formula is used-
$H=\frac{1}{2}(V+M+A-C)$
where H is the number of orbitals involved in hybridization.
V is the number of monovalent atoms.
C is the charge on the cation.
A is the charge on the anion.

- Iodine is a p-block element and it has 7 valence electrons. From this, we can calculate the hybridization $s{{p}^{3}}{{d}^{3}}$ .

- The $s{{p}_{3}}{{d}_{3}}$hybridization has five bonds in a plane, one bond above the plane and one bond below the plane giving a pentagonal bipyramidal geometry.

- Seven hybrid orbitals are not equivalent hybrid orbitals because five of them are directed towards the corners of a regular pentagon while the remaining two are directed above and below the plane.

- In pentagonal bipyramidal geometry, the bond angle is $72{}^\circ$ and $90{}^\circ$ .

So, the given statement is true.

Additional Information:
- Hybridization is the concept of mixing atomic orbitals to form new hybrid orbitals of equal energies and suitable for the qualitative description of atomic bonding properties.

- Following is the list of hybridization and their geometry-

Type of hybridization	No.of hybrid orbitals involved	Bond angle	Structure
sp	2	$180{}^\circ$	Linear
$s{{p}^{2}}$	3	$120{}^\circ$	Plane triangle
$s{{p}^{3}}$	4	$109.5{}^\circ$	Tetrahedral
$s{{p}^{2}}d$	4	$90{}^\circ$	Square planar
$s{{p}^{3}}{{d}^{2}}$	5	$90{}^\circ \And 120{}^\circ$	Trigonal bipyramidal
$s{{p}^{3}}{{d}^{2}}$	6	$90{}^\circ$	Octahedral
$s{{p}^{3}}{{d}^{3}}$	7	$90{}^\circ \And 72{}^\circ$	Pentagonal bipyramidal

Note: Iodine is a black, shiny crystalline solid which when heated sublimes to form a purple vapor. Iodine was first used for producing images on a piece of metal and those images were called daguerreotypes. Iodine salts in the present time are used in pharmaceuticals and disinfectants, printing inks, as catalysts, and animal feed supplements. Iodine is added in small amounts to table salt to avoid deficiency of it. The radioactive iodine-131 is sometimes used to treat thyroid cancers.