Materials Data on Ta4NiS8 by Materials Project
Ta2NiS4(TaS2)2 crystallizes in the trigonal P-3m1 space group. The structure is two-dimensional and consists of one Ta2NiS4 sheet oriented in the (0, 0, 1) direction and two TaS2 sheets oriented in the (0, 0, 1) direction. In the Ta2NiS4 sheet, Ta+3.50+ is bonded to six S2- atoms to form distorted TaS6 pentagonal pyramids that share corners with six equivalent NiS6 octahedra, edges with six equivalent TaS6 pentagonal pyramids, and a faceface with one NiS6 octahedra. The corner-sharing octahedral tilt angles are 47°. There are three shorter (2.49 Å) and three longer (2.51 Å) Ta–S bond lengths. Ni2+ is bonded to six equivalent S2- atoms to form NiS6 octahedra that share corners with twelve equivalent TaS6 pentagonal pyramids, edges with six equivalent NiS6 octahedra, and faces with two equivalent TaS6 pentagonal pyramids. All Ni–S bond lengths are 2.42 Å. There are two inequivalent S2- sites. In the first S2- site, S2- is bonded to three equivalent Ta+3.50+ and three equivalent Ni2+ atoms to form a mixture of distorted edge and corner-sharing STa3Ni3 pentagonal pyramids. In the second S2- site, S2- is bonded in a 3-coordinate geometry to three equivalent Ta+3.50+ atoms. In each TaS2 sheet, Ta+3.50+ is bonded to six S2- atoms to form distorted edge-sharing TaS6 pentagonal pyramids. All Ta–S bond lengths are 2.49 Å. There are two inequivalent S2- sites. In the first S2- site, S2- is bonded in a 3-coordinate geometry to three equivalent Ta+3.50+ atoms. In the second S2- site, S2- is bonded in a 3-coordinate geometry to three equivalent Ta+3.50+ atoms.