Prediction of the lowest energy structure of Sn(BH4)2 and its electronic properties
摘要
The stability of borohydrides M(BH4)n is related to the electron donor properties of metal atoms M. The binding strength of hydrogen is dominated by the B-H bonds in borohydrides M(BH4)n. The crystal structures of Sn(BH4)2 are determined by using the particle-swarm optimization algorithm combined with the density functional theory, and the stabilities and electronic properties are systematically compared with Sn(BH4)4 and M(BH4)2 (M = Mg, Ca). The stability and charge transfer of metal cations Mn+ to BH4− anions is the minimum for Sn(BH4)2. The B-H covalent interactions in Sn(BH4)2 are stronger than that in α-Sn(BH4)4 and M(BH4)2 (M = Mg, Ca), and the M-H covalent interactions in α-Sn(BH4)2 are weaker than that in α-Sn(BH4)4 and slightly stronger than that in M(BH4)2 (M = Mg, Ca).