Rare earth metal ruthenium gallides R2Ru3Ga9 with Y2Co3Ga9 type structure

The twelve isotypic intermetallic compounds R2Ru3Ga9 with R = Y, La-Nd, Sm, Gd-Tm were prepared by are-melting of the elemental components. Their crystal structure was determined from single-crystal X-ray data of Dy2Ru3Ga9: Cmcm, a = 1279.3(2) pm, b = 755.6(1) pm, c = 964.7(1) pm, Z = 4, A = 0.020 for 671 structure factors and 42 variable parameters. All atomic positions have within two standard deviations ideal occupancies (occupancy values vary between 98.8(5) and 101.2(6)%). The structure is briefly discussed, emphasizing its relation to other structures with a high content of gallium or aluminum.