Rietveld refinement of the crystal structure of alpha-Be3N2 and the experimental determination of optical band gaps for Mg3N2, Ca3N2 and CaMg2N2

摘要

alpha-Be3N2 powder was obtained by reacting Be metal with dry, flowing N-2 at 1600 K. The product contained 5.9(7) wt.% of BeO. The anti-bixbyite structure suggested earlier was verified through Rietveld refinement on the basis of X-ray powder data (Ia (3) over bar (#206); a = 814.518(6) pm). The optical band gaps of alpha-Be3N2, Mg3N2 and Ca3N2 are compared with newly measured values for Mg3N2, Ca3N2 and CaMg2N2. [References: 35]