Structure determination of magnesium boron nitride, Mg3BN3, from X-ray powder diffraction data

Abstract

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)/k. 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,p = 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 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 electrondensity map has been calculated from the structurefactor data using the maximum-entropy method.

MgNB9, a new magnesium nitridoboride

“…Hiraguchi et al, 1991), which is about the same as was found in the present study (Table 1). White circles indicate N, grey circles indicate B and dark-grey circles indicate Mg atoms.…”

Reactions of alkaline earth metals and nitrogen in sealed niobium ampoules: the formation of MgZn2 type intermetallic phases in the presence of nitrogen and the new compound Ba5[NbN4]N

“…Table 7 Selected properties of Ae, AeMg 2 , Ae-Mg-N and Ae-Nb-N compounds closely provided the radii for the rare earth elements in their lower oxidation states, 2.1 and 2.0, respectively [34], are used. The most likely nitrogen site would be located inside the Mg bipyramids (Wyckoff position 2b), a structural motif which is also found in Mg 3 BN 3 [30]. Table 8 shows that Table 8 Properties of AeMg 2 compounds according to our results the Mg-N bond lengths in the Mg bipyramid are plausible when compared to those found in Mg 3 BN 3 .…”

Ca4Mg5Ge3N10 and Sr2Mg3GaN4.33: Two Mg‐Containing Nitrides and Their Structural Relation to (Sr,Ba)2Si5N8

“…A trigonal coordination environment of Mg ions is unusual, but has already been reported for Mg 3 BN 3 . Additionally, further nitrides, namely, CaMg 2 GaN 3 and CaMg 2 Ga 2 N 4 , exhibit comparable surroundings of disordered Mg/Ga sites.…”