The structure of `lCl_(2)^(-)` is:

Options

A. trigonal
B. trigonal bipyramidal
C. octahedral
D. square planar.

Explanation

To determine the structure of the ion \( \text{ICl}_2^- \), we can follow these steps:

### Step 1: Count the Valence Electrons
First, we need to count the total number of valence electrons in the ion.
- Iodine (I) is in group 17 and has 7 valence electrons.
- Each chlorine (Cl) atom also has 7 valence electrons, and there are 2 chlorine atoms, contributing \( 2 \times 7 = 14 \) electrons.
- The negative charge on the ion indicates that we have one extra electron.

So, the total number of valence electrons is:
\[ 7 \, (\text{from I}) + 14 \, (\text{from 2 Cl}) + 1 \, (\text{extra from negative charge}) = 22 \, \text{valence electrons} \]

### Step 2: Draw the Lewis Structure
Next, we will draw the Lewis structure for \( \text{ICl}_2^- \).
- Place iodine in the center because it is less electronegative than chlorine.
- Connect the two chlorine atoms to iodine with single bonds. This uses 4 electrons (2 for each bond).
- Now, we have \( 22 - 4 = 18 \) electrons left.
- Distribute the remaining electrons to satisfy the octet rule. Each chlorine will get 6 electrons (3 lone pairs), using up 12 electrons, leaving us with \( 18 - 12 = 6 \) electrons.
- Place the remaining 6 electrons as 3 lone pairs on the iodine atom.

### Step 3: Determine the Molecular Geometry
Now we need to determine the molecular geometry of \( \text{ICl}_2^- \).
- Iodine has 2 bonded pairs (from the I-Cl bonds) and 3 lone pairs.
- According to VSEPR theory, the arrangement of electron pairs around the central atom (iodine) will be trigonal bipyramidal.
- However, since we are only considering the bonded pairs for the molecular shape, the shape of \( \text{ICl}_2^- \) will be linear, as the lone pairs will occupy the equatorial positions to minimize repulsion.

### Step 4: Final Structure
The final structure of \( \text{ICl}_2^- \) can be represented as follows:
- Iodine in the center with two chlorine atoms at opposite ends, and three lone pairs on iodine.

### Summary
- The Lewis structure shows iodine with two single bonds to chlorine and three lone pairs.
- The molecular geometry is linear due to the arrangement of the bonded pairs.

### Final Answer
The structure of \( \text{ICl}_2^- \) is linear with a trigonal bipyramidal electron geometry.

---