Intermetallic compounds in the M–Cu–Sn systems with M = Eu, Sr, Ba

Several samples were prepared in the title systems, starting from the elements sealed under argon in Ta crucibles, melting in an induction fornace and annealing at 823 K. Six ternary phases were found: EuCu2Sn2, a = 11.100 (3), b = 4.307 (1), c = 4.824 (1) Å, β = 108.88 (1)°, and SrCu2Sn2, a = 11.197 (4), b = 4.322 (2), c = 4.859 (1) Å, β = 108.43 (1)°, C2/m, CaCu2Sn2-type, closely related to the BaAl4 structure; Sr3Cu8Sn4, a = 9.3280 (2), c = 7.8826 (4) Å, P63mc, Nd3Co8Sn4-type, ordered variant of the BaLi4-type; SrCu4Sn2, a = 8.176 (1), c = 7.799 (1) Å, I4/mcm, CaNi4Sn2-type; SrCu9Sn4, a = 8.663 (1), c = 12.457 (2) Å, and BaCu9Sn4, a = 8.717 (1), c = 12.545 (2) Å, I4/mcm, LaFe9Si4-type, ordered variant of the NaZn13 structure. The structure of the first compound was refined by the Rietveld method, while single crystal data were used for the others. Some remarks are given on the crystal chemistry of the encountered and related structure types.