Mg7P6(HO6)4 crystallizes in the triclinic P-1 space group. There are four inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to one O(10), one O(2), one O(3), one O(8), and two equivalent O(5) atoms to form MgO6 octahedra that share  a cornercorner with one Mg(2)O6 octahedra,  a cornercorner with one P(3)O4 tetrahedra, corners with two equivalent P(1)O4 tetrahedra, corners with three equivalent P(2)O4 tetrahedra,  an edgeedge with one Mg(1)O6 octahedra, and  an edgeedge with one Mg(4)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles are 63°. In the second Mg site, Mg(2) is bonded to two equivalent O(11), two equivalent O(2), and two equivalent O(7) atoms to form MgO6 octahedra that share corners with two equivalent Mg(1)O6 octahedra, corners with two equivalent P(1)O4 tetrahedra, corners with two equivalent P(2)O4 tetrahedra, corners with two equivalent P(3)O4 tetrahedra, and corners with two equivalent Mg(4)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 63°. In the third Mg site, Mg(3) is bonded to one O(1), one O(12), one O(4), one O(9), and two equivalent O(6) atoms to form MgO6 octahedra that share corners with two equivalent P(1)O4 tetrahedra, corners with two equivalent P(2)O4 tetrahedra, corners with two equivalent P(3)O4 tetrahedra,  an edgeedge with one Mg(3)O6 octahedra, and  an edgeedge with one Mg(4)O5 trigonal bipyramid. In the fourth Mg site, Mg(4) is bonded to one O(1), one O(11), one O(3), one O(8), and one O(9) atom to form MgO5 trigonal bipyramids that share  a cornercorner with one Mg(2)O6 octahedra,  a cornercorner with one P(2)O4 tetrahedra, corners with two equivalent P(1)O4 tetrahedra, corners with two equivalent P(3)O4 tetrahedra,  an edgeedge with one Mg(1)O6 octahedra, and  an edgeedge with one Mg(3)O6 octahedra. The corner-sharing octahedral tilt angles are 68°. There are three inequivalent P sites. In the first P site, 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  a cornercorner with one Mg(2)O6 octahedra, corners with two equivalent Mg(1)O6 octahedra, corners with two equivalent Mg(3)O6 octahedra, and corners with two equivalent Mg(4)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 41-60°. In the second P site, P(2) is bonded to one O(5), one O(6), one O(7), and one O(8) atom to form PO4 tetrahedra that share  a cornercorner with one Mg(2)O6 octahedra, corners with two equivalent Mg(3)O6 octahedra, corners with three equivalent Mg(1)O6 octahedra, and  a cornercorner with one Mg(4)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 25-56°. In the third P site, P(3) is bonded to one O(10), one O(11), one O(12), and one O(9) atom to form PO4 tetrahedra that share  a cornercorner with one Mg(1)O6 octahedra,  a cornercorner with one Mg(2)O6 octahedra, corners with two equivalent Mg(3)O6 octahedra, and corners with two equivalent Mg(4)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 32-58°. There are two inequivalent H sites. In the first H site, H(1) is bonded in a linear geometry to one O(4) and one O(7) atom. In the second H site, H(2) is bonded in a linear geometry to one O(10) and one O(12) atom. There are twelve inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Mg(3), one Mg(4), and one P(1) atom. In the second O site, O(2) is bonded in a trigonal planar geometry to one Mg(1), one Mg(2), and one P(1) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Mg(1), one Mg(4), and one P(1) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Mg(3), one P(1), and one H(1) atom. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to two equivalent Mg(1) and one P(2) atom. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to two equivalent Mg(3) and one P(2) atom. In the seventh O site, O(7) is bonded in a distorted T-shaped geometry to one Mg(2), one P(2), and one H(1) atom. In the eighth O site, O(8) is bonded in a distorted trigonal planar geometry to one Mg(1), one Mg(4), and one P(2) atom. In the ninth O site, O(9) is bonded in a distorted trigonal planar geometry to one Mg(3), one Mg(4), and one P(3) atom. In the tenth O site, O(10) is bonded in a distorted trigonal planar geometry to one Mg(1), one P(3), and one H(2) atom. In the eleventh O site, O(11) is bonded in a trigonal planar geometry to one Mg(2), one Mg(4), and one P(3) atom. In the twelfth O site, O(12) is bonded in a 3-coordinate geometry to one Mg(3), one P(3), and one H(2) atom.
Mg7P6(HO6)4 crystallizes in the triclinic P-1 space group. There are four inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to one O(10), one O(2), one O(3), one O(8), and two equivalent O(5) atoms to form MgO6 octahedra that share  a cornercorner with one Mg(2)O6 octahedra,  a cornercorner with one P(3)O4 tetrahedra, corners with two equivalent P(1)O4 tetrahedra, corners with three equivalent P(2)O4 tetrahedra,  an edgeedge with one Mg(1)O6 octahedra, and  an edgeedge with one Mg(4)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles are 63°. The Mg(1)-O(10) bond length is 2.03 Å. The Mg(1)-O(2) bond length is 2.11 Å. The Mg(1)-O(3) bond length is 2.20 Å. The Mg(1)-O(8) bond length is 2.06 Å. There is one shorter (2.04 Å) and one longer (2.06 Å) Mg(1)-O(5) bond length. In the second Mg site, Mg(2) is bonded to two equivalent O(11), two equivalent O(2), and two equivalent O(7) atoms to form MgO6 octahedra that share corners with two equivalent Mg(1)O6 octahedra, corners with two equivalent P(1)O4 tetrahedra, corners with two equivalent P(2)O4 tetrahedra, corners with two equivalent P(3)O4 tetrahedra, and corners with two equivalent Mg(4)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 63°. Both Mg(2)-O(11) bond lengths are 2.23 Å. Both Mg(2)-O(2) bond lengths are 2.13 Å. Both Mg(2)-O(7) bond lengths are 2.05 Å. In the third Mg site, Mg(3) is bonded to one O(1), one O(12), one O(4), one O(9), and two equivalent O(6) atoms to form MgO6 octahedra that share corners with two equivalent P(1)O4 tetrahedra, corners with two equivalent P(2)O4 tetrahedra, corners with two equivalent P(3)O4 tetrahedra,  an edgeedge with one Mg(3)O6 octahedra, and  an edgeedge with one Mg(4)O5 trigonal bipyramid. The Mg(3)-O(1) bond length is 2.04 Å. The Mg(3)-O(12) bond length is 2.08 Å. The Mg(3)-O(4) bond length is 2.04 Å. The Mg(3)-O(9) bond length is 2.09 Å. There is one shorter (2.04 Å) and one longer (2.06 Å) Mg(3)-O(6) bond length. In the fourth Mg site, Mg(4) is bonded to one O(1), one O(11), one O(3), one O(8), and one O(9) atom to form MgO5 trigonal bipyramids that share  a cornercorner with one Mg(2)O6 octahedra,  a cornercorner with one P(2)O4 tetrahedra, corners with two equivalent P(1)O4 tetrahedra, corners with two equivalent P(3)O4 tetrahedra,  an edgeedge with one Mg(1)O6 octahedra, and  an edgeedge with one Mg(3)O6 octahedra. The corner-sharing octahedral tilt angles are 68°. The Mg(4)-O(1) bond length is 2.12 Å. The Mg(4)-O(11) bond length is 2.05 Å. The Mg(4)-O(3) bond length is 2.06 Å. The Mg(4)-O(8) bond length is 2.00 Å. The Mg(4)-O(9) bond length is 2.05 Å. There are three inequivalent P sites. In the first P site, 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  a cornercorner with one Mg(2)O6 octahedra, corners with two equivalent Mg(1)O6 octahedra, corners with two equivalent Mg(3)O6 octahedra, and corners with two equivalent Mg(4)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 41-60°. The P(1)-O(1) bond length is 1.53 Å. The P(1)-O(2) bond length is 1.54 Å. The P(1)-O(3) bond length is 1.52 Å. The P(1)-O(4) bond length is 1.58 Å. In the second P site, P(2) is bonded to one O(5), one O(6), one O(7), and one O(8) atom to form PO4 tetrahedra that share  a cornercorner with one Mg(2)O6 octahedra, corners with two equivalent Mg(3)O6 octahedra, corners with three equivalent Mg(1)O6 octahedra, and  a cornercorner with one Mg(4)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 25-56°. The P(2)-O(5) bond length is 1.52 Å. The P(2)-O(6) bond length is 1.53 Å. The P(2)-O(7) bond length is 1.55 Å. The P(2)-O(8) bond length is 1.54 Å. In the third P site, P(3) is bonded to one O(10), one O(11), one O(12), and one O(9) atom to form PO4 tetrahedra that share  a cornercorner with one Mg(1)O6 octahedra,  a cornercorner with one Mg(2)O6 octahedra, corners with two equivalent Mg(3)O6 octahedra, and corners with two equivalent Mg(4)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 32-58°. The P(3)-O(10) bond length is 1.51 Å. The P(3)-O(11) bond length is 1.52 Å. The P(3)-O(12) bond length is 1.59 Å. The P(3)-O(9) bond length is 1.53 Å. There are two inequivalent H sites. In the first H site, H(1) is bonded in a linear geometry to one O(4) and one O(7) atom. The H(1)-O(4) bond length is 1.05 Å. The H(1)-O(7) bond length is 1.40 Å. In the second H site, H(2) is bonded in a linear geometry to one O(10) and one O(12) atom. The H(2)-O(10) bond length is 1.57 Å. The H(2)-O(12) bond length is 1.02 Å. There are twelve inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Mg(3), one Mg(4), and one P(1) atom. In the second O site, O(2) is bonded in a trigonal planar geometry to one Mg(1), one Mg(2), and one P(1) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Mg(1), one Mg(4), and one P(1) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Mg(3), one P(1), and one H(1) atom. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to two equivalent Mg(1) and one P(2) atom. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to two equivalent Mg(3) and one P(2) atom. In the seventh O site, O(7) is bonded in a distorted T-shaped geometry to one Mg(2), one P(2), and one H(1) atom. In the eighth O site, O(8) is bonded in a distorted trigonal planar geometry to one Mg(1), one Mg(4), and one P(2) atom. In the ninth O site, O(9) is bonded in a distorted trigonal planar geometry to one Mg(3), one Mg(4), and one P(3) atom. In the tenth O site, O(10) is bonded in a distorted trigonal planar geometry to one Mg(1), one P(3), and one H(2) atom. In the eleventh O site, O(11) is bonded in a trigonal planar geometry to one Mg(2), one Mg(4), and one P(3) atom. In the twelfth O site, O(12) is bonded in a 3-coordinate geometry to one Mg(3), one P(3), and one H(2) atom.