[Ga(en)(3)][Ga3Se7(en)] center dot H2O: A gallium chalcogenide with chains of [Ga3Se6Se2/2(en)](3-) bicycles

Abstract

The new selenidogallate [Ga(en)(3)][Ga3Se7,(en)]. H2O (I) was produced from a ethylendiamine suspension of Ga and Se at 130 degrees C. I crystallizes in the orthorhombic space group Pna2(1) with unit constants a=1347.9(3)pm, b=961.6(1)pm, c=1967.6(4)pm and Z=4. The crystal structure contains an anion so far not observed in gallium chalcogenides. It is built from [Ga3Se6Se2/2(en)](3-) bicycles of three (GaL4)-L-III tetrahedra (L = en, Se) connected via selenium corners to linear chains. The cations, Ga-III ions coordinated by three ethylendiamine in a distorted octahedral geometry are positioned in the holes of the hexagonal rod packing of these chains.