Question

In the crystal of zinc sulphide, zinc occupies tetrahedral voids. What is the coordination number of zinc?

Answer 1

In the crystal structure of zinc sulphide (ZnS), particularly in the zinc blende (sphalerite) form, Zn²⁺ ions occupy tetrahedral voids created by the close-packed arrangement of S²⁻ ions.

In a tetrahedral geometry, each Zn²⁺ ion is surrounded by 4 sulphide ions, and each sulphide ion is also surrounded by 4 zinc ions. The coordination number of zinc in ZnS is 4.