Synthesis, Crystal Structure, and Thermal Decomposition of Strontium Amidoborane

Strontium amidoborane, Sr(NH2BH3)(2), is synthesized by gently milling the powder mixtures of SrH2 and ammonia borane (in a 1:2 molar ratio), followed by isothermally processing the postmilled mixtures at 45 degrees C for 2 h. It is found that Sr(NH2BH3)(2) crystallizes with a monoclinic structure in space group C2, with lattice parameters a = 8.1660(4) angstrom, b = 5.0969(3) angstrom, c = 6.7258(4) angstrom, and beta = 94.392(4)degrees, and with Z = 2. In the structure, each Sr2+ bonds with two [NH2BH3](2-) ions with a Sr-N distance of 2.68 angstrom. Thermal analyses show that the decomposition of Sr(NH2BH3)(2) into Sr(NBH)(2) and H-2 initiates at about 60 degrees C and becomes violent as the temperature increases to 93 degrees C in the heating process at a rate of 2 degrees C min(-1). With the release of H-2, a considerable amount of NH3 and small amounts of B2H6 are also emitted due to the decomposition of Sr(NBH)(2).