CRYSTAL-STRUCTURE OF ZNTE III AT 16 GPA

The long-uncertain crystal structure of ZnTe phase III, stable above 11 GPa, has been determined at 16 GPa using angle-dispersive powder-diffraction techniques with an image-plate area-detector and synchrotron radiation. The structure is orthorhombic, space group Cmcm, and is site ordered. This is a new high-pressure structure, which can be derived by distortion of the rocksalt structure. But the coordination is quite different from NaCl: There are only five nearest neighbors (all unlike) around each atom at similar to 2.7 Angstrom and then three next-nearest-neighbors (of which two are like atoms) at 3.0-3.4 Angstrom.