Zinc blende structure
The zinc blende structure or sphalerite structure describes a type of crystal structure in which a number of weakly polarized ionic compounds crystallize. Due to the ionic radius ratios in sphalerite ( zinc blende , zinc sulfide , ZnS), the sulfide anions form a cubic close packing of spheres in the form of a face-centered cubic unit cell (KfZ, fcc), in which the smaller zinc cations are regularly in half (4) of the total 8 Stop the tetrahedral gaps .
Like the diamond structure , the zinc blende structure consists of a face-centered cubic lattice and the base {(0,0,0), (1 / 4.1 / 4.1 / 4)}. In contrast to the one in which both crystallographic layers are occupied by carbon atoms, here S ions are on (0,0,0) and Zn ions are on (1 / 4.1 / 4.1 / 4). This reduces the symmetry from cubic-hexakisoctahedral to cubic-hexakistrahedral. The tetragyre <100> becomes a tetragyroid , the trigyroid <111> becomes a trigyre , a mirror plane (100) and a digyre <110> disappear. See also axis of rotation .
In addition to the namesake zinc blende (ZnS), several other materials - mainly semiconductors - crystallize in this crystal structure. These include the I-VII, II-VI and III-V compound semiconductors . The most important representative is probably the gallium arsenide (GaAs)
Competing with the zinc blende structure is the hexagonal wurtzite structure , in which other important semiconductors crystallize, including GaN . The illustration on the right gives an important comparative overview for the applications.
literature
- Martin Okrusch, Siegfried Matthes: Mineralogy: An introduction to special mineralogy, petrology and deposit science . 7th edition. Springer Verlag, Berlin, Heidelberg, New York 2005, ISBN 3-540-23812-3 , pp. 34 .
- Paul Ramdohr , Hugo Strunz : Klockmann's textbook of mineralogy . 16th edition. Ferdinand Enke Verlag, 1978, ISBN 3-432-82986-8 , pp. 133 .
- Flash: 3D Crystal Viewer: zinc blende structure