Materials Data on Na2(TaSe2)3 by Materials Project

Na2(TaSe2)3 crystallizes in the trigonal R32 space group. The structure is three-dimensional. Na1+ is bonded in a 6-coordinate geometry to six Se2- atoms. There are three shorter (2.97 Å) and three longer (2.98 Å) Na–Se bond lengths. There are three inequivalent Ta+3.33+ sites. In the first Ta+3.33+ site, Ta+3.33+ is bonded to six equivalent Se2- atoms to form distorted edge-sharing TaSe6 pentagonal pyramids. There are three shorter (2.61 Å) and three longer (2.63 Å) Ta–Se bond lengths. In the second Ta+3.33+ site, Ta+3.33+ is bonded to six equivalent Se2- atoms to form distorted edge-sharing TaSe6 pentagonal pyramids. All Ta–Se bond lengths are 2.63 Å. In the third Ta+3.33+ site, Ta+3.33+ is bonded to six equivalent Se2- atoms to form distorted edge-sharing TaSe6 pentagonal pyramids. There are four shorter (2.62 Å) and two longer (2.63 Å) Ta–Se bond lengths. There are two inequivalent Se2- sites. In the first Se2- site, Se2- is bonded to two equivalent Na1+ and three equivalent Ta+3.33+ atoms to form a mixture of distorted corner, edge, and face-sharing SeNa2Ta3 square pyramids. In the second Se2- site, Se2- is bonded to two equivalent Na1+ and three Ta+3.33+ atoms to form a mixture of distorted corner, edge, and face-sharing SeNa2Ta3 trigonal bipyramids.