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Structure determination of magnesium boron nitride, Mg 3 BN 3 , from X‐ray powder diffraction data
Author(s) -
Hiraguchi H.,
Hashizume H.,
Fukunaga O.,
Takenaka A.,
Sakata M.
Publication year - 1991
Publication title -
journal of applied crystallography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.429
H-Index - 162
ISSN - 1600-5767
DOI - 10.1107/s0021889891001334
Subject(s) - crystallography , powder diffraction , crystal structure , ab initio , rietveld refinement , magnesium , boron nitride , boron , chemistry , materials science , metallurgy , nanotechnology , organic chemistry
The crystal structure of magnesium boron nitride in the low‐pressure phase, Mg 3 BN 3 ( L ), has been solved ab initio from X‐ray powder data. The cell is hexagonal (space group P 6 3 / 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 ( R wp = 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 , Mg 2+ at positions B and C and Mg 2+ with three coordinating N atoms at positions B ′ and C ′, although Mg 3 BN 3 ( 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.