Crystal growth and structure analysis of a new scandium aluminum boride Sc2AlB6

Single crystals of a new ternary boride Sc2AlB6 were obtained from the Sc-A l-B system using high-temperature Al melts under an argon atmosphere. The g rowth conditions for large crystals were established, Sc2AlB6 crystals were obtained in the form of needle-like rectangles extending along the directi on of the b axis or in the form of thick platelets with large c planes, The crystals were examined by powder X-ray diffraction and chemical analyses, and the crystal structure of Sc2AlB6, was investigated by single-crystal X- ray diffractometry, The crystal structure of Sc2AlB6 is of the Y2ReB6 type with the space group Pbam and the unit cell parameters are a = 0.8937(3) nm , b = 1.1226(3) nm, c = 0.3433(1) nm, V = 344.4(1) x 10(-3) nm(3), Z = 4, T he structure refinement converged at an R(F-2) value of 0.046 for 1545 refl ections. The structural characteristics of Sc2AlB6 are discussed. (C) 2000 Academic Press.