Question

In zinc blende structure :
(A). zinc ions occupy half of the tetrahedral sites .
(B). each $Z{n^{2 + }}$ The ion is surrounded by six sulphide ions .
(C). each ${S^{2 - }}$ ion is surrounded by six $Z{n^{3 + }}$ ions .
(D). it has $bcc$ structure

Answer 1

Hint:Zinc Blende refers to the mineral $ZnS$ . It comes in two forms: sphalerite and wurtzite. Both forms have tetrahedral arrangement. The zinc blende structure has “diamond-type-network” and at some different temperature $ZnS$ can exist as wurtzite structure.

Complete step by step answer:
Zinc blende or $ZnS$ also known as sphalerite has a cubic close packing structure also known as face – centred cubic structure.
The $Fcc$ (face – centred cubic) system has lattice points on the faces of the cubes, each of which gives exactly one-half contribution. The coordination number is 12 for FCC.
Coordination numbers refers to the number of the nearest neighbours of the central atom in structure.
In zinc blende structure, zinc ions occupy half of the tetrahedral sites. Each of the ions is 4 – coordinate and has local geometry.
1/2 of the tetrahedral sites that are four of the eight octants of the cube occupied by $Z{n^{2 + }}$ so therefore option A and option D both are the correct ones.

ADDITIONAL INFORMATION:
Talking about the thermal stability of the structure of $ZnS$ , the sphalerite structure is favoured at ${\text{298K}}$ by ${\text{13}}\,{\text{KJ/mol}}$, but at ${\text{1296K}}$ the transition of structure occurs to wurtzite one.
Wurtzite has hexagonal close packing structure (HCP). In this structure, ${\text{12}}$ ions are in the corners of each unit cell that creates a hexagonal prism altogether. The transformation of structure to wurtzite occurs only because of thermal stability of the structure.

Note: $ZnS$ has a FCC structure where the sulphide ions are present at the corners and $Zn$ ions occupy half of the tetrahedral voids .