Structure of strontium thiocyanate trihydrate, Sr(SCN)2.3H2O, at 295 and 125 K

Sr(SCN)2.3H2O, Mr = 257.82, monoclinic, P21/n. At T= 295 K: a = 9.501(1), b = 7.140(1), c = 13.470(2) A, β = 94.27(1)0, V = 911.3(2)A3, Z = 4, Dx = 1.879 g cm-3, λ(Mo Kα) = 0.71069 A, μ = 61.4 cm-1, F(000) = 504, final R = 0.029 for 1458 independent reflections; at T = 125 K: a= 9.452(2), B = 7.103(2), c = 13.373(3)A, β = 94.51(2)0, V = 895.1(4)A3, Z = 4, Dx = 1.913 g cm-3, μ = 62.9 cm-1, final R = 0.031 for 1511 independent reflections. The structure contains SrSN4(H2O)3 polyhedra which are linked by the SCN groups into chains of composition Sr(SCN)2.3H2O. The water molecules form exclusive O--H...S type hydrogen bonds which are all oriented approximately perpendicular to the acceptor SCN groups. (orig.)