10.17188/1202617
None Available
Materials Data on K2Ta15O32 by Materials Project
LBNL Materials Project; Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
2017
Specialized Mix
36 MATERIALS SCIENCE
crystal structure
K2Ta15O32
K-O-Ta
The Materials Project
2017
en
K2Ta15O32 crystallizes in the trigonal R-3 space group. The structure is three-dimensional. K1+ is bonded to twelve O2- atoms to form distorted KO12 cuboctahedra that share corners with six TaO6 octahedra, edges with three equivalent KO12 cuboctahedra, edges with three equivalent TaO6 octahedra, edges with three equivalent TaO5 square pyramids, and faces with three equivalent TaO6 octahedra. The corner-sharing octahedra tilt angles range from 40–57°. There are a spread of K–O bond distances ranging from 3.01–3.24 Å. There are four inequivalent Ta+4.13+ sites. In the first Ta+4.13+ site, Ta+4.13+ is bonded to six equivalent O2- atoms to form TaO6 octahedra that share corners with six equivalent KO12 cuboctahedra and corners with six equivalent TaO6 octahedra. The corner-sharing octahedral tilt angles are 34°. All Ta–O bond lengths are 2.00 Å. In the second Ta+4.13+ site, Ta+4.13+ is bonded to six O2- atoms to form TaO6 octahedra that share a cornercorner with one KO12 cuboctahedra, corners with two TaO6 octahedra, corners with three equivalent TaO5 square pyramids, an edgeedge with one KO12 cuboctahedra, edges with two equivalent TaO6 octahedra, and a faceface with one KO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 34–43°. There are a spread of Ta–O bond distances ranging from 1.90–2.12 Å. In the third Ta+4.13+ site, Ta+4.13+ is bonded to five O2- atoms to form TaO5 square pyramids that share corners with four TaO6 octahedra, corners with four equivalent TaO5 square pyramids, an edgeedge with one KO12 cuboctahedra, and an edgeedge with one TaO6 octahedra. The corner-sharing octahedra tilt angles range from 7–53°. There are a spread of Ta–O bond distances ranging from 2.05–2.19 Å. In the fourth Ta+4.13+ site, Ta+4.13+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with three equivalent TaO6 octahedra, corners with three equivalent TaO5 square pyramids, and edges with three equivalent TaO5 square pyramids. The corner-sharing octahedral tilt angles are 43°. There are three shorter (1.97 Å) and three longer (2.05 Å) Ta–O bond lengths. There are six inequivalent O2- sites. In the first O2- site, O2- is bonded in a 3-coordinate geometry to one K1+ and three Ta+4.13+ atoms. In the second O2- site, O2- is bonded in a T-shaped geometry to three Ta+4.13+ atoms. In the third O2- site, O2- is bonded in a distorted trigonal planar geometry to three Ta+4.13+ atoms. In the fourth O2- site, O2- is bonded in a bent 150 degrees geometry to one K1+ and two Ta+4.13+ atoms. In the fifth O2- site, O2- is bonded in a distorted water-like geometry to two equivalent K1+ and two equivalent Ta+4.13+ atoms. In the sixth O2- site, O2- is bonded in a 3-coordinate geometry to three equivalent Ta+4.13+ atoms.