The PrPS4 type structure and a filled variant: the compounds TbPS4 and LiEuPS4

Colourless single crystals of TbPS4 (a = 10.696(2), c = 19.053(4) Aa) were obtained by reaction of the elements (750 C; 30 h). The compound crystallizes with the PrPS4 type structure (I41/acd; Z = 16). The structure consists of isolated PS4 tetrahedra each surrounded by four Tb3+ cations. Both crystallographically different Tb3+ cations are coordinated by eight sulfur atoms which are part of four PS4 tetrahedra. Orange single crystals of LiEuPS4 (a = 11.498(2), c = 19.882(4) Aa) were prepared by reaction of Eu and P with Li2S4 (700 C; 20 h). The crystal structure corresponds to the PrPS4 type, in which tubes running along [001] are occupied by Li atoms, which are surrounded by four S atoms in strongly distorted tetrahedra. LiS4 and PS4 tetrahedra are connected via common edges into alternating chains. (orig.)