BiMg2PO6 crystallizes in the orthorhombic Cmcm space group. Mg(1) is bonded to one O(3), two equivalent O(1), and two equivalent O(2) atoms to form distorted MgO5 trigonal bipyramids that share corners with three equivalent P(1)O4 tetrahedra, corners with two equivalent Mg(1)O5 trigonal bipyramids, and  an edgeedge with one Mg(1)O5 trigonal bipyramid. Bi(1) is bonded in a 4-coordinate geometry to four equivalent O(1) atoms. P(1) is bonded to two equivalent O(2) and two equivalent O(3) atoms to form PO4 tetrahedra that share corners with six equivalent Mg(1)O5 trigonal bipyramids. There are three inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Mg(1) and two equivalent Bi(1) atoms to form a mixture of corner and edge-sharing OMg2Bi2 tetrahedra. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to two equivalent Mg(1) and one P(1) atom. In the third O site, O(3) is bonded in a bent 150 degrees geometry to one Mg(1) and one P(1) atom.
BiMg2PO6 crystallizes in the orthorhombic Cmcm space group. Mg(1) is bonded to one O(3), two equivalent O(1), and two equivalent O(2) atoms to form distorted MgO5 trigonal bipyramids that share corners with three equivalent P(1)O4 tetrahedra, corners with two equivalent Mg(1)O5 trigonal bipyramids, and  an edgeedge with one Mg(1)O5 trigonal bipyramid. The Mg(1)-O(3) bond length is 1.95 Å. Both Mg(1)-O(1) bond lengths are 2.03 Å. Both Mg(1)-O(2) bond lengths are 2.06 Å. Bi(1) is bonded in a 4-coordinate geometry to four equivalent O(1) atoms. All Bi(1)-O(1) bond lengths are 2.21 Å. P(1) is bonded to two equivalent O(2) and two equivalent O(3) atoms to form PO4 tetrahedra that share corners with six equivalent Mg(1)O5 trigonal bipyramids. Both P(1)-O(2) bond lengths are 1.55 Å. Both P(1)-O(3) bond lengths are 1.52 Å. There are three inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Mg(1) and two equivalent Bi(1) atoms to form a mixture of corner and edge-sharing OMg2Bi2 tetrahedra. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to two equivalent Mg(1) and one P(1) atom. In the third O site, O(3) is bonded in a bent 150 degrees geometry to one Mg(1) and one P(1) atom.