The basis is two ions, a sodium cation and a chlorine anion. The crystal lattice parameter is 0.563 nm. The diagram shows both a unit cell with ion locations indicated (a) and a space filling model (b ...

and the hexagonal Wurtzite (lower diagram). In the zinc blend structure the sulphur ions form an fcc structure and the zinc ions occupy half of the tetrahedral sites in this structure to attain charge ...

RECENTLY, with the increase of the resolving power of the electron microscope, it has become possible to make a direct observation of a crystal lattice composed of large molecules. J. W.