MgCrP2O7 crystallizes in the triclinic P1 space group. Mg(1) is bonded in a 5-coordinate geometry to one O(1), one O(2), one O(4), one O(6), and one O(7) atom. Cr(1) is bonded to one O(1), one O(2), one O(3), one O(4), and one O(6) atom to form distorted CrO5 trigonal bipyramids 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(2), one O(3), one O(5), and one O(7) atom to form PO4 tetrahedra that share  a cornercorner with one P(2)O4 tetrahedra and corners with two equivalent Cr(1)O5 trigonal bipyramids. In the second P site, P(2) is bonded to one O(1), one O(4), one O(5), and one O(6) atom to form PO4 tetrahedra that share  a cornercorner with one P(1)O4 tetrahedra and corners with three equivalent Cr(1)O5 trigonal bipyramids. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a distorted T-shaped geometry to one Mg(1), one Cr(1), and one P(2) atom. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Mg(1), one Cr(1), and one P(1) atom. In the third O site, O(3) is bonded in a distorted bent 150 degrees geometry to one Cr(1) and one P(1) atom. In the fourth O site, O(4) is bonded in a distorted T-shaped geometry to one Mg(1), one Cr(1), and one P(2) atom. In the fifth O site, O(5) is bonded in a bent 120 degrees geometry to one P(1) and one P(2) atom. In the sixth O site, O(6) is bonded in a 3-coordinate geometry to one Mg(1), one Cr(1), and one P(2) atom. In the seventh O site, O(7) is bonded in a bent 120 degrees geometry to one Mg(1) and one P(1) atom.
MgCrP2O7 crystallizes in the triclinic P1 space group. Mg(1) is bonded in a 5-coordinate geometry to one O(1), one O(2), one O(4), one O(6), and one O(7) atom. The Mg(1)-O(1) bond length is 2.02 Å. The Mg(1)-O(2) bond length is 1.98 Å. The Mg(1)-O(4) bond length is 2.39 Å. The Mg(1)-O(6) bond length is 2.04 Å. The Mg(1)-O(7) bond length is 1.96 Å. Cr(1) is bonded to one O(1), one O(2), one O(3), one O(4), and one O(6) atom to form distorted CrO5 trigonal bipyramids that share corners with two equivalent P(1)O4 tetrahedra and corners with three equivalent P(2)O4 tetrahedra. The Cr(1)-O(1) bond length is 2.37 Å. The Cr(1)-O(2) bond length is 2.14 Å. The Cr(1)-O(3) bond length is 2.07 Å. The Cr(1)-O(4) bond length is 2.05 Å. The Cr(1)-O(6) bond length is 2.17 Å. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(2), one O(3), one O(5), and one O(7) atom to form PO4 tetrahedra that share  a cornercorner with one P(2)O4 tetrahedra and corners with two equivalent Cr(1)O5 trigonal bipyramids. The P(1)-O(2) bond length is 1.56 Å. The P(1)-O(3) bond length is 1.51 Å. The P(1)-O(5) bond length is 1.66 Å. The P(1)-O(7) bond length is 1.52 Å. In the second P site, P(2) is bonded to one O(1), one O(4), one O(5), and one O(6) atom to form PO4 tetrahedra that share  a cornercorner with one P(1)O4 tetrahedra and corners with three equivalent Cr(1)O5 trigonal bipyramids. The P(2)-O(1) bond length is 1.54 Å. The P(2)-O(4) bond length is 1.53 Å. The P(2)-O(5) bond length is 1.62 Å. The P(2)-O(6) bond length is 1.55 Å. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a distorted T-shaped geometry to one Mg(1), one Cr(1), and one P(2) atom. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Mg(1), one Cr(1), and one P(1) atom. In the third O site, O(3) is bonded in a distorted bent 150 degrees geometry to one Cr(1) and one P(1) atom. In the fourth O site, O(4) is bonded in a distorted T-shaped geometry to one Mg(1), one Cr(1), and one P(2) atom. In the fifth O site, O(5) is bonded in a bent 120 degrees geometry to one P(1) and one P(2) atom. In the sixth O site, O(6) is bonded in a 3-coordinate geometry to one Mg(1), one Cr(1), and one P(2) atom. In the seventh O site, O(7) is bonded in a bent 120 degrees geometry to one Mg(1) and one P(1) atom.