Zinc blende 1: introduction

To go directly to the unit cell structure, click the link to page 3 below.

Zinc blende, often known as sphalerite, is made of zinc sulfide. It is difficult to identify because of its variable lustre and colour, and because its abundant cleavage planes are usually tricky to find. Indeed the name "sphalerite" comes from the Greek for "treacherous rock" and "blende" is German for "blind" or "deceiving". Crystals of zinc blende sparkle greatly, which is no doubt related to the fact that its structure is a close relative of diamond's. There is also a polymorph called wurtzite, which is based on hexagonal rather than cubic close-packing of the sulfide ions.

A fragment of the bulk structure of zinc blende is shown to the left. The sulfide ions are blue and the zincs are grey.

In the structure on the left the relative size of the ions is to scale, and nearest-neighbour ions are virtually in contact. In future pages the ions will not be shown in contact as it obscures the internal structure of the lattice. Rather, they will be scaled to half their atomic radius, ie one eighth of their volume. In any case, the determination of ion size has its problems. What x-ray diffraction determines most accurately are the positions of the nuclei in the lattice.

Go to page 2 to look at the structure in a different representation.

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