Ba3SiI2, a Double Salt of Barium Iodide and the Zintl Phase Ba2Si

Abstract Reacting Ba 2 X (X=Si, Ge) with a melt of BaI 2 , new compounds of the composition Ba 3 I 2 X were found. These are the simplest representatives of double salts between Zintl phases and halides. The isotypic structures were refined by single-crystal X-ray data ( Fddd , a =10.057(2), b =14.064(3), c =29.526(4) A, R / R w =0.04/0.07 for X =Si, and a =10.064(2), b =14.082(2), c =29.605(4) A, R / R w =0.03/0.07 for X =Ge). Magnetic measurements show Ba 3 I 2 Si to be diamagnetic with a mol susceptibility of 7.7×10 −5 cm 3 /mol. This is in accordance with conductivity measurements and LMTO band structure calculations which show a semiconducting behavior with an electronic band gap of about 0.4 eV.