Materials Data on K2Na2Nd4Nb2O13 by Materials Project
K2Na2Nd4Nb2O13 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. K1+ is bonded in a 10-coordinate geometry to ten O2- atoms. There are a spread of K–O bond distances ranging from 2.85–3.31 Å. Na1+ is bonded to five O2- atoms to form distorted NaO5 trigonal bipyramids that share corners with five equivalent NbO5 trigonal bipyramids and edges with two equivalent NdO7 pentagonal bipyramids. There are two shorter (2.31 Å) and three longer (2.35 Å) Na–O bond lengths. There are two inequivalent Nd3+ sites. In the first Nd3+ site, Nd3+ is bonded to seven O2- atoms to form distorted NdO7 pentagonal bipyramids that share a cornercorner with one NdO7 pentagonal bipyramid, an edgeedge with one NdO7 pentagonal bipyramid, edges with two equivalent NaO5 trigonal bipyramids, and edges with two equivalent NbO5 trigonal bipyramids. There are a spread of Nd–O bond distances ranging from 2.41–2.50 Å. In the second Nd3+ site, Nd3+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Nd–O bond distances ranging from 2.40–2.61 Å. Nb5+ is bonded to five O2- atoms to form NbO5 trigonal bipyramids that share corners with five equivalent NaO5 trigonal bipyramids and edges with two equivalent NdO7 pentagonal bipyramids. There are a spread of Nb–O bond distances ranging from 1.86–2.02 Å. There are seven inequivalent O2- sites. In the first O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent K1+, one Na1+, two Nd3+, and one Nb5+ atom. In the second O2- site, O2- is bonded in a 6-coordinate geometry to two equivalent K1+, one Na1+, two Nd3+, and one Nb5+ atom. In the third O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent K1+, one Na1+, two Nd3+, and one Nb5+ atom. In the fourth O2- site, O2- is bonded in a 6-coordinate geometry to four equivalent K1+, one Na1+, and one Nb5+ atom. In the fifth O2- site, O2- is bonded to four Nd3+ atoms to form ONd4 tetrahedra that share corners with eight ONaNd2Nb tetrahedra and edges with two equivalent ONd4 tetrahedra. In the sixth O2- site, O2- is bonded to one Na1+, two Nd3+, and one Nb5+ atom to form distorted corner-sharing ONaNd2Nb tetrahedra. In the seventh O2- site, O2- is bonded to four Nd3+ atoms to form a mixture of edge and corner-sharing ONd4 tetrahedra.