`ICI_3` is an orange colored solid that dimerizes in solid state as `I_2Cl_6`Based on VSEPR theory , number of 90 degree Cl-l-Cl bond angles is …….. In the dimeric species.

Explanation

To solve the problem, we need to analyze the dimeric structure of ICl3, which is I2Cl6, and determine the number of 90-degree Cl-I-Cl bond angles based on VSEPR theory.

### Step-by-Step Solution:

1. **Identify the Dimeric Structure**:
- ICl3 exists as a dimer in the solid state, forming I2Cl6.
- The structure can be visualized with two iodine atoms at the center and chlorine atoms surrounding them.

2. **Visualize the Geometry**:
- In I2Cl6, each iodine atom is bonded to three chlorine atoms.
- The bonding involves coordinate bonds, where each Cl atom shares its lone pair with the iodine atom.

3. **Determine the Bond Angles**:
- According to VSEPR theory, the arrangement around each iodine atom is trigonal planar due to the three bonding pairs of electrons.
- In a trigonal planar arrangement, the bond angles between the chlorine atoms around each iodine atom are 120 degrees.

4. **Count the Cl-I-Cl Bond Angles**:
- For each iodine atom, there are three Cl-I bonds.
- The Cl-I-Cl bond angles are formed between the chlorine atoms bonded to the same iodine atom.
- Since there are two iodine atoms in the dimer, we need to consider the Cl-I-Cl angles for both iodine centers.

5. **Calculate Total 90-Degree Angles**:
- In the I2Cl6 structure, the Cl-I-Cl bond angles are not 90 degrees; they are 120 degrees.
- However, the question specifically asks for the number of 90-degree Cl-I-Cl bond angles.
- Since there are no 90-degree angles in the dimeric structure, the answer is 0.

### Final Answer:
The number of 90-degree Cl-I-Cl bond angles in the dimeric species I2Cl6 is **0**.