KNd9(SiO4)6O2 crystallizes in the trigonal P3 space group. K(1) is bonded in a 9-coordinate geometry to three equivalent O(4), three equivalent O(7), and three equivalent O(9) atoms. There are five inequivalent Nd sites. In the first Nd site, Nd(1) is bonded in a 7-coordinate geometry to one O(1), one O(3), one O(5), one O(6), one O(7), one O(8), and one O(9) atom. In the second Nd site, Nd(2) is bonded in a 7-coordinate geometry to one O(10), one O(2), one O(4), one O(5), one O(6), one O(7), and one O(8) atom. In the third Nd site, Nd(3) is bonded in a 6-coordinate geometry to three equivalent O(4) and three equivalent O(9) atoms. In the fourth Nd site, Nd(4) is bonded in a 9-coordinate geometry to three equivalent O(10), three equivalent O(3), and three equivalent O(6) atoms. In the fifth Nd site, Nd(5) is bonded in a 9-coordinate geometry to three equivalent O(10), three equivalent O(3), and three equivalent O(8) atoms. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded in a tetrahedral geometry to one O(3), one O(5), one O(7), and one O(9) atom. In the second Si site, Si(2) is bonded in a tetrahedral geometry to one O(10), one O(4), one O(6), and one O(8) atom. There are ten inequivalent O sites. In the first O site, O(8) is bonded in a 4-coordinate geometry to one Nd(1), one Nd(2), one Nd(5), and one Si(2) atom. In the second O site, O(9) is bonded in a 4-coordinate geometry to one K(1), one Nd(1), one Nd(3), and one Si(1) atom. In the third O site, O(10) is bonded in a 4-coordinate geometry to one Nd(2), one Nd(4), one Nd(5), and one Si(2) atom. In the fourth O site, O(1) is bonded in a trigonal planar geometry to three equivalent Nd(1) atoms. In the fifth O site, O(2) is bonded in a trigonal planar geometry to three equivalent Nd(2) atoms. In the sixth O site, O(3) is bonded in a 4-coordinate geometry to one Nd(1), one Nd(4), one Nd(5), and one Si(1) atom. In the seventh O site, O(4) is bonded in a 4-coordinate geometry to one K(1), one Nd(2), one Nd(3), and one Si(2) atom. In the eighth O site, O(5) is bonded in a 1-coordinate geometry to one Nd(1), one Nd(2), and one Si(1) atom. In the ninth O site, O(6) is bonded in a 1-coordinate geometry to one Nd(1), one Nd(2), one Nd(4), and one Si(2) atom. In the tenth O site, O(7) is bonded in a 1-coordinate geometry to one K(1), one Nd(1), one Nd(2), and one Si(1) atom.
KNd9(SiO4)6O2 crystallizes in the trigonal P3 space group. K(1) is bonded in a 9-coordinate geometry to three equivalent O(4), three equivalent O(7), and three equivalent O(9) atoms. All K(1)-O(4) bond lengths are 2.64 Å. All K(1)-O(7) bond lengths are 2.98 Å. All K(1)-O(9) bond lengths are 2.70 Å. There are five inequivalent Nd sites. In the first Nd site, Nd(1) is bonded in a 7-coordinate geometry to one O(1), one O(3), one O(5), one O(6), one O(7), one O(8), and one O(9) atom. The Nd(1)-O(1) bond length is 2.29 Å. The Nd(1)-O(3) bond length is 2.72 Å. The Nd(1)-O(5) bond length is 2.55 Å. The Nd(1)-O(6) bond length is 2.45 Å. The Nd(1)-O(7) bond length is 2.51 Å. The Nd(1)-O(8) bond length is 2.47 Å. The Nd(1)-O(9) bond length is 2.45 Å. In the second Nd site, Nd(2) is bonded in a 7-coordinate geometry to one O(10), one O(2), one O(4), one O(5), one O(6), one O(7), and one O(8) atom. The Nd(2)-O(10) bond length is 2.48 Å. The Nd(2)-O(2) bond length is 2.31 Å. The Nd(2)-O(4) bond length is 2.59 Å. The Nd(2)-O(5) bond length is 2.41 Å. The Nd(2)-O(6) bond length is 2.58 Å. The Nd(2)-O(7) bond length is 2.42 Å. The Nd(2)-O(8) bond length is 2.54 Å. In the third Nd site, Nd(3) is bonded in a 6-coordinate geometry to three equivalent O(4) and three equivalent O(9) atoms. All Nd(3)-O(4) bond lengths are 2.44 Å. All Nd(3)-O(9) bond lengths are 2.47 Å. In the fourth Nd site, Nd(4) is bonded in a 9-coordinate geometry to three equivalent O(10), three equivalent O(3), and three equivalent O(6) atoms. All Nd(4)-O(10) bond lengths are 2.51 Å. All Nd(4)-O(3) bond lengths are 2.44 Å. All Nd(4)-O(6) bond lengths are 2.79 Å. In the fifth Nd site, Nd(5) is bonded in a 9-coordinate geometry to three equivalent O(10), three equivalent O(3), and three equivalent O(8) atoms. All Nd(5)-O(10) bond lengths are 2.51 Å. All Nd(5)-O(3) bond lengths are 2.45 Å. All Nd(5)-O(8) bond lengths are 2.75 Å. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded in a tetrahedral geometry to one O(3), one O(5), one O(7), and one O(9) atom. The Si(1)-O(3) bond length is 1.66 Å. The Si(1)-O(5) bond length is 1.65 Å. The Si(1)-O(7) bond length is 1.65 Å. The Si(1)-O(9) bond length is 1.63 Å. In the second Si site, Si(2) is bonded in a tetrahedral geometry to one O(10), one O(4), one O(6), and one O(8) atom. The Si(2)-O(10) bond length is 1.65 Å. The Si(2)-O(4) bond length is 1.61 Å. The Si(2)-O(6) bond length is 1.66 Å. The Si(2)-O(8) bond length is 1.65 Å. There are ten inequivalent O sites. In the first O site, O(8) is bonded in a 4-coordinate geometry to one Nd(1), one Nd(2), one Nd(5), and one Si(2) atom. In the second O site, O(9) is bonded in a 4-coordinate geometry to one K(1), one Nd(1), one Nd(3), and one Si(1) atom. In the third O site, O(10) is bonded in a 4-coordinate geometry to one Nd(2), one Nd(4), one Nd(5), and one Si(2) atom. In the fourth O site, O(1) is bonded in a trigonal planar geometry to three equivalent Nd(1) atoms. In the fifth O site, O(2) is bonded in a trigonal planar geometry to three equivalent Nd(2) atoms. In the sixth O site, O(3) is bonded in a 4-coordinate geometry to one Nd(1), one Nd(4), one Nd(5), and one Si(1) atom. In the seventh O site, O(4) is bonded in a 4-coordinate geometry to one K(1), one Nd(2), one Nd(3), and one Si(2) atom. In the eighth O site, O(5) is bonded in a 1-coordinate geometry to one Nd(1), one Nd(2), and one Si(1) atom. In the ninth O site, O(6) is bonded in a 1-coordinate geometry to one Nd(1), one Nd(2), one Nd(4), and one Si(2) atom. In the tenth O site, O(7) is bonded in a 1-coordinate geometry to one K(1), one Nd(1), one Nd(2), and one Si(1) atom.