| Popis: |
The crystal structure of rutile-type magnesium deuteride,α-MgD2, has been studied byin situneutron powder diffraction at room temperature and pressures up to 9.3 GPa. The bulk modulusB0= 49(2) GPa is about half, the linear compressibilities (0.0063/GPa alongaand 0.0041/GPa alongc) are about twice and the variation of the free positional parameterxabout six times the values for the isostructural magnesium fluoride, indicating the strong polarizability of the deuteride anion. Under pressure the MgD6octahedra are more compressed (four Mg–D distances at 199(1), two at 173(1) pm) than at ambient pressure (195.1(1), 194.8(2) pm) and the structural arrangement becomes more CaCl2like, although no structural phase transition has been observed. |
