Zaymiey

🧪 Chemistry  ·  Solid State  ·  NEET & JEE

In the zinc blende (ZnS) structure, S²⁻ ions form FCC and Zn²⁺ ions occupy half the tetrahedral voids. The coordination numbers of Zn²⁺ and S²⁻ respectively are:

Answer: 4 and 4.

  • A 4 and 4
  • B 4 and 8
  • C 6 and 6
  • D 8 and 4

Correct answer: A. 4 and 4

Explanation: In zinc blende, Zn²⁺ occupies tetrahedral voids (CN = 4) and each S²⁻ is surrounded by 4 Zn²⁺ (CN = 4). Both have coordination number 4.

Cubic Unit Cells: Atom PositionsSimple CubicCN=6, 52.4% packedBody-Centred (BCC)CN=8, 68% packedFace-Centred (FCC)CN=12, 74% packed (densest)Corner atoms (shared by 8 cells) shown lighter; body/face-centre atoms shown solid

The three cubic unit cells: Simple Cubic has atoms only at corners; Body-Centred adds one atom at the centre; Face-Centred adds one atom at the centre of each of the 6 faces, giving the highest packing efficiency.

Concept context

Explore the ordered world of crystalline solids: unit cells, packing, defects, and how structure determines electrical and magnetic properties.

Read the full Solid State notes →