Characterization of beryllium-boron-bearing materials by parallel electron energy-loss spectroscopy (PEELS)

The stoichiometry of a set of commercial and laboratory-synthesized Be-B-bearing materials was determined by parallel electron energy-loss spectroscopy (PEELS), The Be and B K edges are well separated in energy, allowing easy determination of the elemental ratios, PEELS analyses of materials with reported compositions of "Be(2)B" and "Be(2)B(3)" provided stoichiometries near Be(2.8)B and Be(4)B(5), respectively, We confirmed an earlier report of Be(0.6)(+/-(0.1)) B(5.9(+/-0.7))C, a material with the alpha-rhombohedral B structure. We also synthesized and characterized Be(0.5(+/-0.1))B(4.9(+/-0.3))N, a new ternary material with the alpha-rhombohedral B structure with refined hexagonal cell parameters of a(h)=5.487(5) Angstrom and c(h)=12.486(14) Angstrom. By comparison of the features at the core-loss edges of Be(0.5(+/-0.1))B(4.9(+/-0.3))N, we conclude that most N forms N(2) pairs between the icosahedra and Be substitutes for B within the icosahedra. (C) 1997 Academic Press.