Crystal structure of sodium gold(I) thiosulfate dihydrate, Na3Au(S2O3)2.2H2O

Abstract

The crystal and molecular structure of Na/sub 3/Au(S/sub 2/O/sub 3/)/sub 2/.2H/sub 2/O has been determined from a single-crystal x-ray diffraction study. The monoclinic space group is P2/sub 1//a with a = 18.206 (6) A, b = 11.355 (6) A, c = 5.436 (4) A, ..beta.. = 97.87 (5)/sup 0/, Z = 4, and d/sub x/ = 3.14 g cm/sup -3/. The structure was refined by full-matrix least squares to a conventional R factor of 0.055 using 1811 nonzero intensities. The gold atom is bonded to two sulfur atoms from two thiosulfate groups in a nearly linear arrangement (S-Au-S = 176.5/sup 0/). The average Au-S, S-S, and S-O bond distances are 2.28 (1), 2.06 (1), and 1.46 (1) A. The three sodium atoms are coordinated to irregular polyhedra of oxygen neighbors; two of the sodium atoms have six such neighbors and one has five. Hydrogen bond lengths are 0-H...S = 3.24 (1) and 3.33 (1) A and 0-H...0 = 2.75 (1) A.