NaCuPO4 crystallizes in the orthorhombic P2_12_12_1 space group. Na(1) is bonded in a 7-coordinate geometry to one O(4), two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms. Cu(1) is bonded to one O(1), one O(2), one O(3), and two equivalent O(4) atoms to form distorted CuO5 trigonal bipyramids that share corners with three equivalent P(1)O4 tetrahedra, corners with two equivalent Cu(1)O5 trigonal bipyramids, and  an edgeedge with one P(1)O4 tetrahedra. P(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form PO4 tetrahedra that share corners with three equivalent Cu(1)O5 trigonal bipyramids and  an edgeedge with one Cu(1)O5 trigonal bipyramid. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to two equivalent Na(1), one Cu(1), and one P(1) atom. In the second O site, O(2) is bonded in a 4-coordinate geometry to two equivalent Na(1), one Cu(1), and one P(1) atom. In the third O site, O(3) is bonded to two equivalent Na(1), one Cu(1), and one P(1) atom to form distorted corner-sharing ONa2CuP trigonal pyramids. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to one Na(1), two equivalent Cu(1), and one P(1) atom.
NaCuPO4 crystallizes in the orthorhombic P2_12_12_1 space group. Na(1) is bonded in a 7-coordinate geometry to one O(4), two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms. The Na(1)-O(4) bond length is 2.49 Å. There is one shorter (2.47 Å) and one longer (2.61 Å) Na(1)-O(1) bond length. There is one shorter (2.47 Å) and one longer (2.72 Å) Na(1)-O(2) bond length. There is one shorter (2.45 Å) and one longer (2.52 Å) Na(1)-O(3) bond length. Cu(1) is bonded to one O(1), one O(2), one O(3), and two equivalent O(4) atoms to form distorted CuO5 trigonal bipyramids that share corners with three equivalent P(1)O4 tetrahedra, corners with two equivalent Cu(1)O5 trigonal bipyramids, and  an edgeedge with one P(1)O4 tetrahedra. The Cu(1)-O(1) bond length is 1.95 Å. The Cu(1)-O(2) bond length is 2.06 Å. The Cu(1)-O(3) bond length is 2.02 Å. There is one shorter (1.93 Å) and one longer (2.36 Å) Cu(1)-O(4) bond length. P(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form PO4 tetrahedra that share corners with three equivalent Cu(1)O5 trigonal bipyramids and  an edgeedge with one Cu(1)O5 trigonal bipyramid. The P(1)-O(1) bond length is 1.55 Å. The P(1)-O(2) bond length is 1.54 Å. The P(1)-O(3) bond length is 1.57 Å. The P(1)-O(4) bond length is 1.58 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to two equivalent Na(1), one Cu(1), and one P(1) atom. In the second O site, O(2) is bonded in a 4-coordinate geometry to two equivalent Na(1), one Cu(1), and one P(1) atom. In the third O site, O(3) is bonded to two equivalent Na(1), one Cu(1), and one P(1) atom to form distorted corner-sharing ONa2CuP trigonal pyramids. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to one Na(1), two equivalent Cu(1), and one P(1) atom.