What type of stoichiometric defect is shown by:
(a) `ZnS` (b) `AgBr`

Explanation

To determine the type of stoichiometric defects exhibited by `ZnS` and `AgBr`, we can analyze each compound step by step.

### Step 1: Analyze `ZnS`
- **Type of Defect**: `ZnS` exhibits a **Frenkel defect**.
- **Explanation**: In a Frenkel defect, an atom (usually a cation) leaves its lattice site and occupies an interstitial site, creating a vacancy in the lattice. In the case of `ZnS`, the zinc ions (Zn²⁺) can move from their lattice positions to interstitial sites, leading to a situation where there are vacancies in the lattice structure. This results in a decrease in density.

### Step 2: Analyze `AgBr`
- **Type of Defect**: `AgBr` exhibits both **Frenkel defect** and **Schottky defect**.
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