NaCaP2O9NO crystallizes in the monoclinic Cc space group. The structure consists of four nitroxyl molecules inside a NaCaP2O9 framework. In the NaCaP2O9 framework, Na(1) is bonded in a 6-coordinate geometry to one O(1), one O(7), two equivalent O(10), and two equivalent O(9) atoms. Ca(1) is bonded to one O(1), one O(2), one O(5), one O(6), one O(7), and one O(8) atom to form distorted CaO6 octahedra that share corners with two equivalent P(1)O4 tetrahedra and corners with three equivalent P(2)O4 tetrahedra. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(4), one O(5), and one O(9) atom to form PO4 tetrahedra that share corners with two equivalent Ca(1)O6 octahedra and  a cornercorner with one P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 48-54°. In the second P site, P(2) is bonded to one O(2), one O(4), one O(6), and one O(8) atom to form PO4 tetrahedra that share corners with three equivalent Ca(1)O6 octahedra and  a cornercorner with one P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 49-56°. There are nine inequivalent O sites. In the first O site, O(7) is bonded in a water-like geometry to one Na(1) and one Ca(1) atom. In the second O site, O(8) is bonded in a distorted bent 120 degrees geometry to one Ca(1) and one P(2) atom. In the third O site, O(9) is bonded in a distorted trigonal planar geometry to two equivalent Na(1) and one P(1) atom. In the fourth O site, O(10) is bonded in an L-shaped geometry to two equivalent Na(1) atoms. In the fifth O site, O(1) is bonded in a distorted trigonal planar geometry to one Na(1), one Ca(1), and one P(1) atom. In the sixth O site, O(2) is bonded in a distorted bent 120 degrees geometry to one Ca(1) and one P(2) atom. In the seventh O site, O(4) is bonded in a bent 120 degrees geometry to one P(1) and one P(2) atom. In the eighth O site, O(5) is bonded in a distorted bent 120 degrees geometry to one Ca(1) and one P(1) atom. In the ninth O site, O(6) is bonded in a bent 120 degrees geometry to one Ca(1) and one P(2) atom.
NaCaP2O9NO crystallizes in the monoclinic Cc space group. The structure consists of four nitroxyl molecules inside a NaCaP2O9 framework. In the NaCaP2O9 framework, Na(1) is bonded in a 6-coordinate geometry to one O(1), one O(7), two equivalent O(10), and two equivalent O(9) atoms. The Na(1)-O(1) bond length is 2.50 Å. The Na(1)-O(7) bond length is 2.42 Å. There is one shorter (2.60 Å) and one longer (2.72 Å) Na(1)-O(10) bond length. There is one shorter (2.26 Å) and one longer (2.39 Å) Na(1)-O(9) bond length. Ca(1) is bonded to one O(1), one O(2), one O(5), one O(6), one O(7), and one O(8) atom to form distorted CaO6 octahedra that share corners with two equivalent P(1)O4 tetrahedra and corners with three equivalent P(2)O4 tetrahedra. The Ca(1)-O(1) bond length is 2.38 Å. The Ca(1)-O(2) bond length is 2.34 Å. The Ca(1)-O(5) bond length is 2.31 Å. The Ca(1)-O(6) bond length is 2.33 Å. The Ca(1)-O(7) bond length is 2.44 Å. The Ca(1)-O(8) bond length is 2.32 Å. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(4), one O(5), and one O(9) atom to form PO4 tetrahedra that share corners with two equivalent Ca(1)O6 octahedra and  a cornercorner with one P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 48-54°. The P(1)-O(1) bond length is 1.53 Å. The P(1)-O(4) bond length is 1.68 Å. The P(1)-O(5) bond length is 1.53 Å. The P(1)-O(9) bond length is 1.51 Å. In the second P site, P(2) is bonded to one O(2), one O(4), one O(6), and one O(8) atom to form PO4 tetrahedra that share corners with three equivalent Ca(1)O6 octahedra and  a cornercorner with one P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 49-56°. The P(2)-O(2) bond length is 1.52 Å. The P(2)-O(4) bond length is 1.61 Å. The P(2)-O(6) bond length is 1.56 Å. The P(2)-O(8) bond length is 1.54 Å. There are nine inequivalent O sites. In the first O site, O(7) is bonded in a water-like geometry to one Na(1) and one Ca(1) atom. In the second O site, O(8) is bonded in a distorted bent 120 degrees geometry to one Ca(1) and one P(2) atom. In the third O site, O(9) is bonded in a distorted trigonal planar geometry to two equivalent Na(1) and one P(1) atom. In the fourth O site, O(10) is bonded in an L-shaped geometry to two equivalent Na(1) atoms. In the fifth O site, O(1) is bonded in a distorted trigonal planar geometry to one Na(1), one Ca(1), and one P(1) atom. In the sixth O site, O(2) is bonded in a distorted bent 120 degrees geometry to one Ca(1) and one P(2) atom. In the seventh O site, O(4) is bonded in a bent 120 degrees geometry to one P(1) and one P(2) atom. In the eighth O site, O(5) is bonded in a distorted bent 120 degrees geometry to one Ca(1) and one P(1) atom. In the ninth O site, O(6) is bonded in a bent 120 degrees geometry to one Ca(1) and one P(2) atom.