MgBi4(P2O7)4 crystallizes in the triclinic P1 space group. Mg(1) is bonded in a 5-coordinate geometry to one O(12), one O(2), one O(20), one O(22), and one O(26) atom. There are four inequivalent Bi sites. In the first Bi site, Bi(1) is bonded to one O(10), one O(17), one O(23), one O(5), one O(6), and one O(8) atom to form BiO6 octahedra that share  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(6)O4 tetrahedra, corners with two equivalent P(5)O4 tetrahedra, and corners with two equivalent P(7)O4 tetrahedra. In the second Bi site, Bi(2) is bonded to one O(13), one O(15), one O(21), one O(27), one O(28), and one O(7) atom to form BiO6 octahedra that share  a cornercorner with one P(2)O4 tetrahedra,  a cornercorner with one P(4)O4 tetrahedra, corners with two equivalent P(3)O4 tetrahedra, and corners with two equivalent P(8)O4 tetrahedra. In the third Bi site, Bi(3) is bonded to one O(12), one O(14), one O(19), one O(2), one O(24), and one O(4) atom to form distorted BiO6 octahedra that share  a cornercorner with one P(3)O4 tetrahedra,  a cornercorner with one P(8)O4 tetrahedra, corners with two equivalent P(2)O4 tetrahedra, and corners with two equivalent P(4)O4 tetrahedra. In the fourth Bi site, Bi(4) is bonded to one O(1), one O(11), one O(25), one O(3), and one O(9) atom to form BiO5 square pyramids that share  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(5)O4 tetrahedra,  a cornercorner with one P(7)O4 tetrahedra, and corners with two equivalent P(6)O4 tetrahedra. There are eight inequivalent P sites. In the first P site, P(1) is bonded to one O(10), one O(11), one O(20), and one O(26) atom to form PO4 tetrahedra that share  a cornercorner with one Bi(1)O6 octahedra,  a cornercorner with one Bi(4)O5 square pyramid, and  a cornercorner with one P(4)O4 tetrahedra. The corner-sharing octahedral tilt angles are 45°. In the second P site, P(2) is bonded to one O(14), one O(18), one O(24), and one O(7) atom to form PO4 tetrahedra that share  a cornercorner with one Bi(2)O6 octahedra, corners with two equivalent Bi(3)O6 octahedra, and  a cornercorner with one P(6)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 36-55°. In the third P site, P(3) is bonded to one O(16), one O(19), one O(27), and one O(28) atom to form PO4 tetrahedra that share  a cornercorner with one Bi(3)O6 octahedra, corners with two equivalent Bi(2)O6 octahedra, and  a cornercorner with one P(7)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 34-51°. In the fourth P site, P(4) is bonded to one O(12), one O(21), one O(26), and one O(4) atom to form PO4 tetrahedra that share  a cornercorner with one Bi(2)O6 octahedra, corners with two equivalent Bi(3)O6 octahedra, and  a cornercorner with one P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 34-66°. In the fifth P site, P(5) is bonded to one O(22), one O(23), one O(5), and one O(9) atom to form PO4 tetrahedra that share corners with two equivalent Bi(1)O6 octahedra,  a cornercorner with one Bi(4)O5 square pyramid, and  a cornercorner with one P(8)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 38-54°. In the sixth P site, P(6) is bonded to one O(1), one O(18), one O(25), and one O(6) atom to form PO4 tetrahedra that share  a cornercorner with one Bi(1)O6 octahedra, corners with two equivalent Bi(4)O5 square pyramids, and  a cornercorner with one P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 46°. In the seventh P site, P(7) is bonded to one O(16), one O(17), one O(3), and one O(8) atom to form PO4 tetrahedra that share corners with two equivalent Bi(1)O6 octahedra,  a cornercorner with one Bi(4)O5 square pyramid, and  a cornercorner with one P(3)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 45-52°. In the eighth P site, P(8) is bonded to one O(13), one O(15), one O(2), and one O(22) atom to form PO4 tetrahedra that share  a cornercorner with one Bi(3)O6 octahedra, corners with two equivalent Bi(2)O6 octahedra, and  a cornercorner with one P(5)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 35-49°. There are twenty-eight inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to one Bi(4) and one P(6) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Mg(1), one Bi(3), and one P(8) atom. In the third O site, O(3) is bonded in a distorted bent 150 degrees geometry to one Bi(4) and one P(7) atom. In the fourth O site, O(4) is bonded in a distorted bent 150 degrees geometry to one Bi(3) and one P(4) atom. In the fifth O site, O(5) is bonded in a distorted bent 120 degrees geometry to one Bi(1) and one P(5) atom. In the sixth O site, O(6) is bonded in a 2-coordinate geometry to one Bi(1) and one P(6) atom. In the seventh O site, O(7) is bonded in a distorted bent 150 degrees geometry to one Bi(2) and one P(2) atom. In the eighth O site, O(8) is bonded in a 2-coordinate geometry to one Bi(1) and one P(7) atom. In the ninth O site, O(9) is bonded in a distorted bent 120 degrees geometry to one Bi(4) and one P(5) atom. In the tenth O site, O(10) is bonded in a distorted single-bond geometry to one Bi(1) and one P(1) atom. In the eleventh O site, O(11) is bonded in a distorted bent 120 degrees geometry to one Bi(4) and one P(1) atom. In the twelfth O site, O(12) is bonded in a 2-coordinate geometry to one Mg(1), one Bi(3), and one P(4) atom. In the thirteenth O site, O(13) is bonded in a distorted bent 120 degrees geometry to one Bi(2) and one P(8) atom. In the fourteenth O site, O(14) is bonded in a distorted bent 120 degrees geometry to one Bi(3) and one P(2) atom. In the fifteenth O site, O(15) is bonded in a distorted bent 150 degrees geometry to one Bi(2) and one P(8) atom. In the sixteenth O site, O(16) is bonded in a bent 150 degrees geometry to one P(3) and one P(7) atom. In the seventeenth O site, O(17) is bonded in a distorted bent 120 degrees geometry to one Bi(1) and one P(7) atom. In the eighteenth O site, O(18) is bonded in a bent 150 degrees geometry to one P(2) and one P(6) atom. In the nineteenth O site, O(19) is bonded in a distorted bent 120 degrees geometry to one Bi(3) and one P(3) atom. In the twentieth O site, O(20) is bonded in a bent 120 degrees geometry to one Mg(1) and one P(1) atom. In the twenty-first O site, O(21) is bonded in a 2-coordinate geometry to one Bi(2) and one P(4) atom. In the twenty-second O site, O(22) is bonded in a 3-coordinate geometry to one Mg(1), one P(5), and one P(8) atom. In the twenty-third O site, O(23) is bonded in a distorted bent 150 degrees geometry to one Bi(1) and one P(5) atom. In the twenty-fourth O site, O(24) is bonded in a distorted bent 150 degrees geometry to one Bi(3) and one P(2) atom. In the twenty-fifth O site, O(25) is bonded in a distorted bent 150 degrees geometry to one Bi(4) and one P(6) atom. In the twenty-sixth O site, O(26) is bonded in a trigonal planar geometry to one Mg(1), one P(1), and one P(4) atom. In the twenty-seventh O site, O(27) is bonded in a distorted bent 120 degrees geometry to one Bi(2) and one P(3) atom. In the twenty-eighth O site, O(28) is bonded in a bent 150 degrees geometry to one Bi(2) and one P(3) atom.
MgBi4(P2O7)4 crystallizes in the triclinic P1 space group. Mg(1) is bonded in a 5-coordinate geometry to one O(12), one O(2), one O(20), one O(22), and one O(26) atom. The Mg(1)-O(12) bond length is 2.03 Å. The Mg(1)-O(2) bond length is 2.05 Å. The Mg(1)-O(20) bond length is 1.99 Å. The Mg(1)-O(22) bond length is 2.41 Å. The Mg(1)-O(26) bond length is 2.16 Å. There are four inequivalent Bi sites. In the first Bi site, Bi(1) is bonded to one O(10), one O(17), one O(23), one O(5), one O(6), and one O(8) atom to form BiO6 octahedra that share  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(6)O4 tetrahedra, corners with two equivalent P(5)O4 tetrahedra, and corners with two equivalent P(7)O4 tetrahedra. The Bi(1)-O(10) bond length is 2.37 Å. The Bi(1)-O(17) bond length is 2.29 Å. The Bi(1)-O(23) bond length is 2.28 Å. The Bi(1)-O(5) bond length is 2.27 Å. The Bi(1)-O(6) bond length is 2.25 Å. The Bi(1)-O(8) bond length is 2.27 Å. In the second Bi site, Bi(2) is bonded to one O(13), one O(15), one O(21), one O(27), one O(28), and one O(7) atom to form BiO6 octahedra that share  a cornercorner with one P(2)O4 tetrahedra,  a cornercorner with one P(4)O4 tetrahedra, corners with two equivalent P(3)O4 tetrahedra, and corners with two equivalent P(8)O4 tetrahedra. The Bi(2)-O(13) bond length is 2.32 Å. The Bi(2)-O(15) bond length is 2.33 Å. The Bi(2)-O(21) bond length is 2.34 Å. The Bi(2)-O(27) bond length is 2.33 Å. The Bi(2)-O(28) bond length is 2.28 Å. The Bi(2)-O(7) bond length is 2.31 Å. In the third Bi site, Bi(3) is bonded to one O(12), one O(14), one O(19), one O(2), one O(24), and one O(4) atom to form distorted BiO6 octahedra that share  a cornercorner with one P(3)O4 tetrahedra,  a cornercorner with one P(8)O4 tetrahedra, corners with two equivalent P(2)O4 tetrahedra, and corners with two equivalent P(4)O4 tetrahedra. The Bi(3)-O(12) bond length is 2.72 Å. The Bi(3)-O(14) bond length is 2.31 Å. The Bi(3)-O(19) bond length is 2.25 Å. The Bi(3)-O(2) bond length is 2.52 Å. The Bi(3)-O(24) bond length is 2.19 Å. The Bi(3)-O(4) bond length is 2.37 Å. In the fourth Bi site, Bi(4) is bonded to one O(1), one O(11), one O(25), one O(3), and one O(9) atom to form BiO5 square pyramids that share  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(5)O4 tetrahedra,  a cornercorner with one P(7)O4 tetrahedra, and corners with two equivalent P(6)O4 tetrahedra. The Bi(4)-O(1) bond length is 2.24 Å. The Bi(4)-O(11) bond length is 2.44 Å. The Bi(4)-O(25) bond length is 2.19 Å. The Bi(4)-O(3) bond length is 2.28 Å. The Bi(4)-O(9) bond length is 2.39 Å. There are eight inequivalent P sites. In the first P site, P(1) is bonded to one O(10), one O(11), one O(20), and one O(26) atom to form PO4 tetrahedra that share  a cornercorner with one Bi(1)O6 octahedra,  a cornercorner with one Bi(4)O5 square pyramid, and  a cornercorner with one P(4)O4 tetrahedra. The corner-sharing octahedral tilt angles are 45°. The P(1)-O(10) bond length is 1.53 Å. The P(1)-O(11) bond length is 1.51 Å. The P(1)-O(20) bond length is 1.53 Å. The P(1)-O(26) bond length is 1.69 Å. In the second P site, P(2) is bonded to one O(14), one O(18), one O(24), and one O(7) atom to form PO4 tetrahedra that share  a cornercorner with one Bi(2)O6 octahedra, corners with two equivalent Bi(3)O6 octahedra, and  a cornercorner with one P(6)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 36-55°. The P(2)-O(14) bond length is 1.53 Å. The P(2)-O(18) bond length is 1.61 Å. The P(2)-O(24) bond length is 1.54 Å. The P(2)-O(7) bond length is 1.54 Å. In the third P site, P(3) is bonded to one O(16), one O(19), one O(27), and one O(28) atom to form PO4 tetrahedra that share  a cornercorner with one Bi(3)O6 octahedra, corners with two equivalent Bi(2)O6 octahedra, and  a cornercorner with one P(7)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 34-51°. The P(3)-O(16) bond length is 1.61 Å. The P(3)-O(19) bond length is 1.53 Å. The P(3)-O(27) bond length is 1.54 Å. The P(3)-O(28) bond length is 1.53 Å. In the fourth P site, P(4) is bonded to one O(12), one O(21), one O(26), and one O(4) atom to form PO4 tetrahedra that share  a cornercorner with one Bi(2)O6 octahedra, corners with two equivalent Bi(3)O6 octahedra, and  a cornercorner with one P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 34-66°. The P(4)-O(12) bond length is 1.54 Å. The P(4)-O(21) bond length is 1.52 Å. The P(4)-O(26) bond length is 1.70 Å. The P(4)-O(4) bond length is 1.51 Å. In the fifth P site, P(5) is bonded to one O(22), one O(23), one O(5), and one O(9) atom to form PO4 tetrahedra that share corners with two equivalent Bi(1)O6 octahedra,  a cornercorner with one Bi(4)O5 square pyramid, and  a cornercorner with one P(8)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 38-54°. The P(5)-O(22) bond length is 1.65 Å. The P(5)-O(23) bond length is 1.53 Å. The P(5)-O(5) bond length is 1.54 Å. The P(5)-O(9) bond length is 1.51 Å. In the sixth P site, P(6) is bonded to one O(1), one O(18), one O(25), and one O(6) atom to form PO4 tetrahedra that share  a cornercorner with one Bi(1)O6 octahedra, corners with two equivalent Bi(4)O5 square pyramids, and  a cornercorner with one P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 46°. The P(6)-O(1) bond length is 1.52 Å. The P(6)-O(18) bond length is 1.61 Å. The P(6)-O(25) bond length is 1.54 Å. The P(6)-O(6) bond length is 1.54 Å. In the seventh P site, P(7) is bonded to one O(16), one O(17), one O(3), and one O(8) atom to form PO4 tetrahedra that share corners with two equivalent Bi(1)O6 octahedra,  a cornercorner with one Bi(4)O5 square pyramid, and  a cornercorner with one P(3)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 45-52°. The P(7)-O(16) bond length is 1.61 Å. The P(7)-O(17) bond length is 1.55 Å. The P(7)-O(3) bond length is 1.51 Å. The P(7)-O(8) bond length is 1.55 Å. In the eighth P site, P(8) is bonded to one O(13), one O(15), one O(2), and one O(22) atom to form PO4 tetrahedra that share  a cornercorner with one Bi(3)O6 octahedra, corners with two equivalent Bi(2)O6 octahedra, and  a cornercorner with one P(5)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 35-49°. The P(8)-O(13) bond length is 1.53 Å. The P(8)-O(15) bond length is 1.51 Å. The P(8)-O(2) bond length is 1.54 Å. The P(8)-O(22) bond length is 1.66 Å. There are twenty-eight inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to one Bi(4) and one P(6) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Mg(1), one Bi(3), and one P(8) atom. In the third O site, O(3) is bonded in a distorted bent 150 degrees geometry to one Bi(4) and one P(7) atom. In the fourth O site, O(4) is bonded in a distorted bent 150 degrees geometry to one Bi(3) and one P(4) atom. In the fifth O site, O(5) is bonded in a distorted bent 120 degrees geometry to one Bi(1) and one P(5) atom. In the sixth O site, O(6) is bonded in a 2-coordinate geometry to one Bi(1) and one P(6) atom. In the seventh O site, O(7) is bonded in a distorted bent 150 degrees geometry to one Bi(2) and one P(2) atom. In the eighth O site, O(8) is bonded in a 2-coordinate geometry to one Bi(1) and one P(7) atom. In the ninth O site, O(9) is bonded in a distorted bent 120 degrees geometry to one Bi(4) and one P(5) atom. In the tenth O site, O(10) is bonded in a distorted single-bond geometry to one Bi(1) and one P(1) atom. In the eleventh O site, O(11) is bonded in a distorted bent 120 degrees geometry to one Bi(4) and one P(1) atom. In the twelfth O site, O(12) is bonded in a 2-coordinate geometry to one Mg(1), one Bi(3), and one P(4) atom. In the thirteenth O site, O(13) is bonded in a distorted bent 120 degrees geometry to one Bi(2) and one P(8) atom. In the fourteenth O site, O(14) is bonded in a distorted bent 120 degrees geometry to one Bi(3) and one P(2) atom. In the fifteenth O site, O(15) is bonded in a distorted bent 150 degrees geometry to one Bi(2) and one P(8) atom. In the sixteenth O site, O(16) is bonded in a bent 150 degrees geometry to one P(3) and one P(7) atom. In the seventeenth O site, O(17) is bonded in a distorted bent 120 degrees geometry to one Bi(1) and one P(7) atom. In the eighteenth O site, O(18) is bonded in a bent 150 degrees geometry to one P(2) and one P(6) atom. In the nineteenth O site, O(19) is bonded in a distorted bent 120 degrees geometry to one Bi(3) and one P(3) atom. In the twentieth O site, O(20) is bonded in a bent 120 degrees geometry to one Mg(1) and one P(1) atom. In the twenty-first O site, O(21) is bonded in a 2-coordinate geometry to one Bi(2) and one P(4) atom. In the twenty-second O site, O(22) is bonded in a 3-coordinate geometry to one Mg(1), one P(5), and one P(8) atom. In the twenty-third O site, O(23) is bonded in a distorted bent 150 degrees geometry to one Bi(1) and one P(5) atom. In the twenty-fourth O site, O(24) is bonded in a distorted bent 150 degrees geometry to one Bi(3) and one P(2) atom. In the twenty-fifth O site, O(25) is bonded in a distorted bent 150 degrees geometry to one Bi(4) and one P(6) atom. In the twenty-sixth O site, O(26) is bonded in a trigonal planar geometry to one Mg(1), one P(1), and one P(4) atom. In the twenty-seventh O site, O(27) is bonded in a distorted bent 120 degrees geometry to one Bi(2) and one P(3) atom. In the twenty-eighth O site, O(28) is bonded in a bent 150 degrees geometry to one Bi(2) and one P(3) atom.