K2AUPS4, TI2AUPS4, K2AUASS4, AND KAU5P2S8 - SYNTHESES, STRUCTURES, AND PROPERTIES OF QUATERNARY GOLD THIOPHOSPHATE AND THIOARSENATE COMPOUNDS

The novel compounds K2AuPS4 (1), Tl2AuPS4 (2), K2AuAsS4 (3), and KAu5P 2S8 (4) have been synthesized by direct reaction of the elements with a molten alkaline polythiophosphate(arsenate) flux at 550 degrees C. T he crystal structures of these compounds have been determined by singl e-crystal X-ray diffraction techniques. 1, 2, and 3 crystallize in the monoclinic space group P2(1)/m. The structures of 1, 2, and 3 consist of infinite, one-dimensional anionic chains running along the crystal lographic b axis. The chains are separated by potassium or thallium io ns. Neighbouring Au atoms are bridged by MS43- tetrahedra (M = P, As) in a trans orientation. Compound 4 crystallizes in the space group P2( 1)/c. The anionic chains of 4 are built up from linear AuS2 dumbbell u nits and PS43- tetrahedra. The chains extend along the [1(1) over bar0 $] and [1(1) over bar0$] direction and are separated by charge balanci ng K+ cations. Each of the compounds was investigated by differential thermal analysis, FT-IR, and solid-state UV/Vis diffuse reflectance sp ectroscopy.