Ca3Au6.61Ga4.39 - A new gallide with a three-dimensional gold-gallium network

Ca3Au6.61Ga4.39 was synthesized by reacting the elements in a glassy carbon crucible under argon in a water-cooled sample chamber in a high-frequency furnace. The compound crystallizes with a new hexagonal structure type, spa ce group P6(3)/mmc: Z = 2, a = 926.6(2), c = 733.1(2) pm, wR2 = 0.0832, 328 F-0(2) values and 20 variables. This structure type consists of a remarkab ly complex three-dimensional [Au6.61Ga4.39] network with significant Au-Au, Au-Ga, and Ga-Ga interactions. The calcium atoms are located within slight ly distorted hexagonal channels of the gold-gallium network. The structural relations to the AlB2 and Er2RhSi3 type structures are discussed.