Na2CoP2O7 crystallizes in the orthorhombic Pnma space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded in a 9-coordinate geometry to one O(2), two equivalent O(1), two equivalent O(5), and four equivalent O(4) atoms. In the second Na site, Na(2) is bonded in a 7-coordinate geometry to one O(5), two equivalent O(2), and four equivalent O(1) atoms. Co(1) is bonded to one O(2), two equivalent O(1), and two equivalent O(4) atoms to form CoO5 trigonal bipyramids that share corners with two equivalent P(2)O4 tetrahedra and corners with three equivalent P(1)O4 tetrahedra. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(2), one O(3), and two equivalent O(1) atoms to form PO4 tetrahedra that share  a cornercorner with one P(2)O4 tetrahedra and corners with three equivalent Co(1)O5 trigonal bipyramids. In the second P site, P(2) is bonded to one O(3), one O(5), and two equivalent O(4) atoms to form PO4 tetrahedra that share  a cornercorner with one P(1)O4 tetrahedra and corners with two equivalent Co(1)O5 trigonal bipyramids. There are five inequivalent O sites. In the first O site, O(3) is bonded in a bent 120 degrees geometry to one P(1) and one P(2) atom. In the second O site, O(4) is bonded in a 2-coordinate geometry to two equivalent Na(1), one Co(1), and one P(2) atom. In the third O site, O(5) is bonded in a 4-coordinate geometry to one Na(2), two equivalent Na(1), and one P(2) atom. In the fourth O site, O(1) is bonded in a 5-coordinate geometry to one Na(1), two equivalent Na(2), one Co(1), and one P(1) atom. In the fifth O site, O(2) is bonded in a 5-coordinate geometry to one Na(1), two equivalent Na(2), one Co(1), and one P(1) atom.
Na2CoP2O7 crystallizes in the orthorhombic Pnma space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded in a 9-coordinate geometry to one O(2), two equivalent O(1), two equivalent O(5), and four equivalent O(4) atoms. The Na(1)-O(2) bond length is 2.54 Å. Both Na(1)-O(1) bond lengths are 2.66 Å. Both Na(1)-O(5) bond lengths are 2.85 Å. There are two shorter (2.80 Å) and two longer (2.94 Å) Na(1)-O(4) bond lengths. In the second Na site, Na(2) is bonded in a 7-coordinate geometry to one O(5), two equivalent O(2), and four equivalent O(1) atoms. The Na(2)-O(5) bond length is 2.21 Å. Both Na(2)-O(2) bond lengths are 2.67 Å. There are two shorter (2.65 Å) and two longer (2.69 Å) Na(2)-O(1) bond lengths. Co(1) is bonded to one O(2), two equivalent O(1), and two equivalent O(4) atoms to form CoO5 trigonal bipyramids that share corners with two equivalent P(2)O4 tetrahedra and corners with three equivalent P(1)O4 tetrahedra. The Co(1)-O(2) bond length is 2.11 Å. Both Co(1)-O(1) bond lengths are 2.09 Å. Both Co(1)-O(4) bond lengths are 2.00 Å. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(2), one O(3), and two equivalent O(1) atoms to form PO4 tetrahedra that share  a cornercorner with one P(2)O4 tetrahedra and corners with three equivalent Co(1)O5 trigonal bipyramids. The P(1)-O(2) bond length is 1.53 Å. The P(1)-O(3) bond length is 1.62 Å. Both P(1)-O(1) bond lengths are 1.54 Å. In the second P site, P(2) is bonded to one O(3), one O(5), and two equivalent O(4) atoms to form PO4 tetrahedra that share  a cornercorner with one P(1)O4 tetrahedra and corners with two equivalent Co(1)O5 trigonal bipyramids. The P(2)-O(3) bond length is 1.66 Å. The P(2)-O(5) bond length is 1.50 Å. Both P(2)-O(4) bond lengths are 1.54 Å. There are five inequivalent O sites. In the first O site, O(3) is bonded in a bent 120 degrees geometry to one P(1) and one P(2) atom. In the second O site, O(4) is bonded in a 2-coordinate geometry to two equivalent Na(1), one Co(1), and one P(2) atom. In the third O site, O(5) is bonded in a 4-coordinate geometry to one Na(2), two equivalent Na(1), and one P(2) atom. In the fourth O site, O(1) is bonded in a 5-coordinate geometry to one Na(1), two equivalent Na(2), one Co(1), and one P(1) atom. In the fifth O site, O(2) is bonded in a 5-coordinate geometry to one Na(1), two equivalent Na(2), one Co(1), and one P(1) atom.