Crystal structure of a new modification of potassium tetrathioantimonate, ß-K3SbS4

Source of material: During our investigations in the system A/NB/Sb/S the compound s-K3SbS4 was obtained under the following conditions. K2S3, Nb, Sb and S, in a 4/1/2/8 ratio, were thoroughly mixed in a dry box. K2S3 was prepared by the reaction of stoichiometric amounts of Κ and S in liquid ammonia under an argon atmosphere. The mixture was then loaded into apyrexglass ampoule which was subsequently evacuated (4x10 mbar) and sealed. The ampoule was heated to 623 Κ for 6 days and afterwards was cooled to roomtemperature with 3K/h. The resulting black-red melt was washed with DMF and dried in vacuum. The product consisted of two components, red crystals of K6Nb4S25 and white transparent crystals of s-K3SbS4-s-K3SbS4 is hygroscopic and must be stored under dry conditions. For X-ray crystal structure determination, a suitable crystal was mounted on a glass fiber and completely covered with glue. Despite these measure the crystal slightly decomposed during