Darstellung und kristallstruktur von K 4Au 6S 5 — ein thioaurat mit anionischen [Au 6S 5]-baugruppen

Abstract

The new compound K 4Au 6S 5 was prepared by reacting a corresponding mixture of potassium sulphide, gold and sulphur at 600 °C. Green-yellow crystals were obtained by cooling the melt slowly. The crystal structure was determined from four-circle diffractometer data and refined to a conventional R of 0.037 for 342 observed reflections. K 4Au 6S 5 crystallizes in the space group P6̄2c with a = 9.631(3) A ̊ , c = 9.856(4) A ̊ and Z = 2. The crystal structure is characterized by anionic [Au 6S 5] groups, stacked along [001] in hexagonal close-packed sense. They are built up from trigonal bipyramids of sulphur atoms, upon whose skew edges lie the gold atoms, so forming a trigonal prism. The coordination of the gold atoms is almost linear. The Au-Au distances within and between the [Au 6] units show weak interactions of the atoms with d 10 configuration.