Materials Data on Ta11(CoSe4)2 by Materials Project
Ta11Co2Se8 crystallizes in the orthorhombic Pnnm space group. The structure is three-dimensional. there are six inequivalent Ta sites. In the first Ta site, Ta is bonded in a 5-coordinate geometry to two equivalent Co and three Se atoms. Both Ta–Co bond lengths are 2.50 Å. There are one shorter (2.56 Å) and two longer (2.75 Å) Ta–Se bond lengths. In the second Ta site, Ta is bonded in a 4-coordinate geometry to one Co and four Se atoms. The Ta–Co bond length is 2.87 Å. There are two shorter (2.64 Å) and two longer (2.68 Å) Ta–Se bond lengths. In the third Ta site, Ta is bonded in a 5-coordinate geometry to two equivalent Co and three Se atoms. Both Ta–Co bond lengths are 2.56 Å. There are one shorter (2.71 Å) and two longer (2.73 Å) Ta–Se bond lengths. In the fourth Ta site, Ta is bonded in a 4-coordinate geometry to one Co and four Se atoms. The Ta–Co bond length is 2.86 Å. There are a spread of Ta–Se bond distances ranging from 2.62–2.78 Å. In the fifth Ta site, Ta is bonded in a 5-coordinate geometry to two equivalent Co and three Se atoms. Both Ta–Co bond lengths are 2.48 Å. There are one shorter (2.62 Å) and two longer (2.76 Å) Ta–Se bond lengths. In the sixth Ta site, Ta is bonded in a distorted square co-planar geometry to two equivalent Co and two equivalent Se atoms. Both Ta–Co bond lengths are 2.77 Å. Both Ta–Se bond lengths are 2.71 Å. Co is bonded in a 9-coordinate geometry to nine Ta atoms. There are four inequivalent Se sites. In the first Se site, Se is bonded in a 3-coordinate geometry to three Ta atoms. In the second Se site, Se is bonded to six Ta atoms to form distorted edge-sharing SeTa6 pentagonal pyramids. In the third Se site, Se is bonded in a 5-coordinate geometry to five Ta atoms. In the fourth Se site, Se is bonded in a 4-coordinate geometry to four Ta atoms.