Ba_4Si_3Br_2:A Double Salt of Barium Bromide and Barium Silicide Containing a Novel Cyclotrisilicide Unit

摘要

A new compound of the com-position Ba_4Si_3Br_2 was obtained by re-acting BaSi with a melt of BaBr_2.Ba_4Si_3Br_2 may be described as a double .The structure was detdermind by single-crystal X-ray diffraction(P2_1c,#alpha=1504.1(2)b=884.5(1),c=880.2(1)pm,#beta#=101.93(2) deg,R=0.041 R_W=0.097).the crystal structure contains isolated barium cations and bromide anions as well as novel singly bonded cyclotrisili-cid units .The electronic structure has been studied by linear Muffin tin orbital (LMTO)band structure calculations which reveal semiconducing behavior with a band gap of about 0.1eV,and by an analysis of the electron localization function.