In solid state, `PCI_5`, is a

Options

A. covalent solid
B. octahedral structure
C. ionic solid with `[PCl_6]^(+)` octahedral and `[PCl_4]^-` tetrahedra
D. ionic solid with `[PCl_4]^+` tetrahedra and `[PCl_6]^-` octahedra

Answer

To solve the question regarding the solid-state structure of PCl5, we can follow these steps:

### Step 1: Understand the phases of PCl5
PCl5 exists in different phases: gaseous, liquid, and solid. In the gaseous and liquid phases, PCl5 exhibits sp³d hybridization and has a trigonal bipyramidal geometry.

**Hint:** Remember that hybridization can change based on the state of matter.

### Step 2: Analyze the solid-state structure
In the solid-state, PCl5 does not retain its molecular form. Instead, it dissociates into ions. In this state, it exists as an ionic solid composed of PCl4⁺ (phosphorus tetrachloride cation) and PCl6⁻ (phosphorus hexachloride anion).

**Hint:** Ionic solids consist of positively and negatively charged ions.

### Step 3: Determine the hybridization of the ions
The PCl4⁺ ion undergoes sp³ hybridization, resulting in a tetrahedral geometry. On the other hand, the PCl6⁻ ion undergoes sp³d² hybridization, leading to an octahedral geometry.

**Hint:** Different ions can have different hybridizations and geometries.

### Step 4: Conclude the solid-state structure of PCl5
Thus, in the solid state, PCl5 is characterized as an ionic solid with PCl4⁺ having a tetrahedral shape and PCl6⁻ having an octahedral shape.

**Hint:** The geometry of ions in ionic solids can provide insights into their structure.

### Final Answer
In solid state, PCl5 is an ionic solid consisting of PCl4⁺ (tetrahedral) and PCl6⁻ (octahedral).

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