ic049270z_si_001.cif (8.88 kB)
Au2(SeO3)2(SeO4): Synthesis and Characterization of a New Noncentrosymmetric Selenite−Selenate
dataset
posted on 2004-09-20, 00:00 authored by Mathias S. Wickleder, Oliver Büchner, Claudia Wickleder, Sherif el Sheik, Gunther Brunklaus, Hellmut EckertThe reaction of elemental gold and selenic acid in Teflon-lined steel autoclaves leads to orange-yellow single
crystals of Au2(SeO3)2(SeO4) (orthorhombic, Z = 4, Cmc21 (No. 36), a = 1689.1(3) pm, b = 630.13(8) pm, c =
832.7(1) pm, V = 886.2(2) Å3, Rall = 0.0452). In the crystal structure, Au3+ is surrounded by four oxygen atoms
of just as many monodentate SeO32- ions in a square planar manner. The linkage of the polyhedra leads to
double chains
in the [001] direction which are connected to puckered layers by SeO42- groups.
The noncentrosymmetric space group could be proved by the observation of an SHG effect upon irridation at 1064
nm that shows an efficiency of about 43% compared to a KDP reference. Upon heating, Au2(SeO3)2(SeO4)
decomposes at about 370 °C in one step yielding elemental gold. The presence of selenite and selenate groups
in the compounds is also obvious from the IR and Raman spectra which show the characteristic bands of both
species. Furthermore, solid-state NMR spectra reveal the different surroundings of the selenium atoms in the
compound.