ISSN:
1600-5767
Source:
Crystallography Journals Online : IUCR Backfile Archive 1948-2001
Topics:
Geosciences
,
Physics
Notes:
The crystal structure of magnesium boron nitride in the low-pressure phase, Mg3BN3(L), has been solved ab initio from X-ray powder data. The cell is hexagonal (space group P63/mmc, Z = 2) with a = 3.54453 (4), c = 16.03536 (30) Å. Initial positional parameters for the Mg atoms were obtained from Patterson functions generated by 50 integrated intensities derived from a whole-powder pattern decomposition. The remaining atoms were located by trial-and-error model building, followed by Rietveld refinements (Rwp = 8.5%). The structure can be described as consisting of ABB′BACC′CA... layers perpendicular to the c axis with linear N=B=N molecular anions at position A, Mg2+ at positions B and C and Mg2+ with three coordinating N atoms at positions B′ and C′, although Mg3BN3(L) is not a layer compound. A very similar structure has also been obtained by applying standard direct methods to the same intensity data. A high-quality electron-density map has been calculated from the structure factor data using the maximum-entropy method.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1107/S0021889891001334
