Materials Data on KCa2Nb3O10 by Materials Project
KCa2Nb3O10 is Pb (Zr_0.50 Ti_0.48) O_3-derived structured and crystallizes in the monoclinic P2_1/m space group. The structure is three-dimensional. there are two inequivalent K1+ sites. In the first K1+ site, K1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of K–O bond distances ranging from 2.84–2.89 Å. In the second K1+ site, K1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of K–O bond distances ranging from 2.77–2.83 Å. There are four inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded in a 10-coordinate geometry to ten O2- atoms. There are a spread of Ca–O bond distances ranging from 2.51–2.87 Å. In the second Ca2+ site, Ca2+ is bonded in a 6-coordinate geometry to eight O2- atoms. There are a spread of Ca–O bond distances ranging from 2.41–2.84 Å. In the third Ca2+ site, Ca2+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Ca–O bond distances ranging from 2.35–2.47 Å. In the fourth Ca2+ site, Ca2+ is bonded to twelve O2- atoms to form distorted CaO12 cuboctahedra that share faces with four NbO6 octahedra. There are a spread of Ca–O bond distances ranging from 2.41–2.96 Å. There are four inequivalent Nb5+ sites. In the first Nb5+ site, Nb5+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Nb–O bond distances ranging from 1.79–2.44 Å. In the second Nb5+ site, Nb5+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Nb–O bond distances ranging from 1.80–2.43 Å. In the third Nb5+ site, Nb5+ is bonded to six O2- atoms to form NbO6 octahedra that share corners with four NbO6 octahedra and faces with two equivalent CaO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 31–34°. There are two shorter (1.96 Å) and four longer (2.04 Å) Nb–O bond lengths. In the fourth Nb5+ site, Nb5+ is bonded to six O2- atoms to form NbO6 octahedra that share corners with four NbO6 octahedra and faces with two equivalent CaO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 31–35°. There are a spread of Nb–O bond distances ranging from 1.97–2.05 Å. There are thirteen inequivalent O2- sites. In the first O2- site, O2- is bonded in a 4-coordinate geometry to two Ca2+ and two Nb5+ atoms. In the second O2- site, O2- is bonded in a distorted single-bond geometry to three K1+ and one Nb5+ atom. In the third O2- site, O2- is bonded to two Ca2+ and two Nb5+ atoms to form a mixture of distorted edge and corner-sharing OCa2Nb2 tetrahedra. In the fourth O2- site, O2- is bonded in a 5-coordinate geometry to three Ca2+ and two Nb5+ atoms. In the fifth O2- site, O2- is bonded to two Ca2+ and two equivalent Nb5+ atoms to form a mixture of distorted edge and corner-sharing OCa2Nb2 tetrahedra. In the sixth O2- site, O2- is bonded in a 2-coordinate geometry to two Ca2+ and two equivalent Nb5+ atoms. In the seventh O2- site, O2- is bonded in a 4-coordinate geometry to two Ca2+ and two Nb5+ atoms. In the eighth O2- site, O2- is bonded to two Ca2+ and two equivalent Nb5+ atoms to form a mixture of distorted edge and corner-sharing OCa2Nb2 tetrahedra. In the ninth O2- site, O2- is bonded in a distorted single-bond geometry to three K1+ and one Nb5+ atom. In the tenth O2- site, O2- is bonded in a 4-coordinate geometry to two Ca2+ and two equivalent Nb5+ atoms. In the eleventh O2- site, O2- is bonded in a 2-coordinate geometry to two Ca2+ and two equivalent Nb5+ atoms. In the twelfth O2- site, O2- is bonded in a 3-coordinate geometry to two Ca2+ and two equivalent Nb5+ atoms. In the thirteenth O2- site, O2- is bonded in a 1-coordinate geometry to three Ca2+ and two Nb5+ atoms.