K8Mg(SiO3)8 crystallizes in the triclinic P1 space group. There are eight inequivalent K sites. In the first K site, K(1) is bonded in a 5-coordinate geometry to one O(13), one O(14), one O(17), one O(24), and one O(6) atom. In the second K site, K(2) is bonded in a 7-coordinate geometry to one O(1), one O(10), one O(14), one O(18), one O(20), one O(23), and one O(5) atom. In the third K site, K(3) is bonded in a 6-coordinate geometry to one O(15), one O(16), one O(17), one O(19), one O(22), and one O(8) atom. In the fourth K site, K(4) is bonded to one O(12), one O(16), one O(18), one O(20), one O(21), one O(3), and one O(7) atom to form distorted KO7 pentagonal bipyramids that share  a cornercorner with one Si(5)O4 tetrahedra,  a cornercorner with one Si(7)O4 tetrahedra,  a cornercorner with one Si(8)O4 tetrahedra, corners with two equivalent Si(4)O4 tetrahedra,  an edgeedge with one Si(3)O4 tetrahedra, and  an edgeedge with one Si(6)O4 tetrahedra. In the fifth K site, K(5) is bonded in a 7-coordinate geometry to one O(14), one O(15), one O(17), one O(2), one O(23), one O(4), and one O(9) atom. In the sixth K site, K(6) is bonded in a 6-coordinate geometry to one O(1), one O(10), one O(16), one O(18), one O(24), and one O(3) atom. In the seventh K site, K(7) is bonded in a 10-coordinate geometry to one Mg(1), one O(11), one O(13), one O(16), one O(17), one O(19), one O(2), one O(21), one O(4), and one O(7) atom. In the eighth K site, K(8) is bonded in a 7-coordinate geometry to one O(1), one O(12), one O(14), one O(15), one O(20), one O(22), and one O(3) atom. Mg(1) is bonded in a distorted see-saw-like geometry to one K(7), one O(13), one O(2), one O(21), and one O(23) atom. There are eight inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(1), one O(13), one O(5), and one O(9) atom to form corner-sharing SiO4 tetrahedra. In the second Si site, Si(2) is bonded to one O(10), one O(14), one O(2), and one O(6) atom to form corner-sharing SiO4 tetrahedra. In the third Si site, Si(3) is bonded to one O(11), one O(15), one O(3), and one O(7) atom to form SiO4 tetrahedra that share  a cornercorner with one Si(5)O4 tetrahedra,  a cornercorner with one Si(7)O4 tetrahedra, and  an edgeedge with one K(4)O7 pentagonal bipyramid. In the fourth Si site, Si(4) is bonded to one O(12), one O(16), one O(4), and one O(8) atom to form SiO4 tetrahedra that share corners with two equivalent K(4)O7 pentagonal bipyramids,  a cornercorner with one Si(6)O4 tetrahedra, and  a cornercorner with one Si(8)O4 tetrahedra. In the fifth Si site, Si(5) is bonded to one O(11), one O(17), one O(21), and one O(5) atom to form SiO4 tetrahedra that share  a cornercorner with one K(4)O7 pentagonal bipyramid,  a cornercorner with one Si(1)O4 tetrahedra, and  a cornercorner with one Si(3)O4 tetrahedra. In the sixth Si site, Si(6) is bonded to one O(12), one O(18), one O(22), and one O(6) atom to form SiO4 tetrahedra that share  a cornercorner with one Si(2)O4 tetrahedra,  a cornercorner with one Si(4)O4 tetrahedra, and  an edgeedge with one K(4)O7 pentagonal bipyramid. In the seventh Si site, Si(7) is bonded to one O(19), one O(23), one O(7), and one O(9) atom to form SiO4 tetrahedra that share  a cornercorner with one K(4)O7 pentagonal bipyramid,  a cornercorner with one Si(1)O4 tetrahedra, and  a cornercorner with one Si(3)O4 tetrahedra. In the eighth Si site, Si(8) is bonded to one O(10), one O(20), one O(24), and one O(8) atom to form SiO4 tetrahedra that share  a cornercorner with one K(4)O7 pentagonal bipyramid,  a cornercorner with one Si(2)O4 tetrahedra, and  a cornercorner with one Si(4)O4 tetrahedra. There are twenty-four inequivalent O sites. In the first O site, O(1) is bonded in a distorted single-bond geometry to one K(2), one K(6), one K(8), and one Si(1) atom. In the second O site, O(2) is bonded in a 2-coordinate geometry to one K(5), one K(7), one Mg(1), and one Si(2) atom. In the third O site, O(3) is bonded in a distorted single-bond geometry to one K(4), one K(6), one K(8), and one Si(3) atom. In the fourth O site, O(4) is bonded in a 1-coordinate geometry to one K(5), one K(7), and one Si(4) atom. In the fifth O site, O(5) is bonded in a distorted bent 120 degrees geometry to one K(2), one Si(1), and one Si(5) atom. In the sixth O site, O(6) is bonded in a 2-coordinate geometry to one K(1), one Si(2), and one Si(6) atom. In the seventh O site, O(7) is bonded in a 2-coordinate geometry to one K(4), one K(7), one Si(3), and one Si(7) atom. In the eighth O site, O(8) is bonded in a 2-coordinate geometry to one K(3), one Si(4), and one Si(8) atom. In the ninth O site, O(9) is bonded in a distorted bent 120 degrees geometry to one K(5), one Si(1), and one Si(7) atom. In the tenth O site, O(10) is bonded in a 2-coordinate geometry to one K(2), one K(6), one Si(2), and one Si(8) atom. In the eleventh O site, O(11) is bonded in a bent 150 degrees geometry to one K(7), one Si(3), and one Si(5) atom. In the twelfth O site, O(12) is bonded in a distorted bent 150 degrees geometry to one K(4), one K(8), one Si(4), and one Si(6) atom. In the thirteenth O site, O(13) is bonded in a 2-coordinate geometry to one K(1), one K(7), one Mg(1), and one Si(1) atom. In the fourteenth O site, O(14) is bonded in a distorted single-bond geometry to one K(1), one K(2), one K(5), one K(8), and one Si(2) atom. In the fifteenth O site, O(15) is bonded in a distorted single-bond geometry to one K(3), one K(5), one K(8), and one Si(3) atom. In the sixteenth O site, O(16) is bonded in a distorted single-bond geometry to one K(3), one K(4), one K(6), one K(7), and one Si(4) atom. In the seventeenth O site, O(17) is bonded in a 1-coordinate geometry to one K(1), one K(3), one K(5), one K(7), and one Si(5) atom. In the eighteenth O site, O(18) is bonded in a distorted single-bond geometry to one K(2), one K(4), one K(6), and one Si(6) atom. In the nineteenth O site, O(19) is bonded in a 3-coordinate geometry to one K(3), one K(7), and one Si(7) atom. In the twentieth O site, O(20) is bonded in a distorted single-bond geometry to one K(2), one K(4), one K(8), and one Si(8) atom. In the twenty-first O site, O(21) is bonded in a 2-coordinate geometry to one K(4), one K(7), one Mg(1), and one Si(5) atom. In the twenty-second O site, O(22) is bonded in a 1-coordinate geometry to one K(3), one K(8), and one Si(6) atom. In the twenty-third O site, O(23) is bonded in a 2-coordinate geometry to one K(2), one K(5), one Mg(1), and one Si(7) atom. In the twenty-fourth O site, O(24) is bonded in a distorted single-bond geometry to one K(1), one K(6), and one Si(8) atom.
K8Mg(SiO3)8 crystallizes in the triclinic P1 space group. There are eight inequivalent K sites. In the first K site, K(1) is bonded in a 5-coordinate geometry to one O(13), one O(14), one O(17), one O(24), and one O(6) atom. The K(1)-O(13) bond length is 3.00 Å. The K(1)-O(14) bond length is 2.81 Å. The K(1)-O(17) bond length is 2.85 Å. The K(1)-O(24) bond length is 2.90 Å. The K(1)-O(6) bond length is 2.91 Å. In the second K site, K(2) is bonded in a 7-coordinate geometry to one O(1), one O(10), one O(14), one O(18), one O(20), one O(23), and one O(5) atom. The K(2)-O(1) bond length is 2.79 Å. The K(2)-O(10) bond length is 3.25 Å. The K(2)-O(14) bond length is 2.77 Å. The K(2)-O(18) bond length is 2.67 Å. The K(2)-O(20) bond length is 2.80 Å. The K(2)-O(23) bond length is 2.78 Å. The K(2)-O(5) bond length is 3.02 Å. In the third K site, K(3) is bonded in a 6-coordinate geometry to one O(15), one O(16), one O(17), one O(19), one O(22), and one O(8) atom. The K(3)-O(15) bond length is 2.70 Å. The K(3)-O(16) bond length is 3.17 Å. The K(3)-O(17) bond length is 3.18 Å. The K(3)-O(19) bond length is 2.90 Å. The K(3)-O(22) bond length is 2.81 Å. The K(3)-O(8) bond length is 2.82 Å. In the fourth K site, K(4) is bonded to one O(12), one O(16), one O(18), one O(20), one O(21), one O(3), and one O(7) atom to form distorted KO7 pentagonal bipyramids that share  a cornercorner with one Si(5)O4 tetrahedra,  a cornercorner with one Si(7)O4 tetrahedra,  a cornercorner with one Si(8)O4 tetrahedra, corners with two equivalent Si(4)O4 tetrahedra,  an edgeedge with one Si(3)O4 tetrahedra, and  an edgeedge with one Si(6)O4 tetrahedra. The K(4)-O(12) bond length is 3.13 Å. The K(4)-O(16) bond length is 3.20 Å. The K(4)-O(18) bond length is 3.14 Å. The K(4)-O(20) bond length is 2.73 Å. The K(4)-O(21) bond length is 2.91 Å. The K(4)-O(3) bond length is 2.94 Å. The K(4)-O(7) bond length is 2.95 Å. In the fifth K site, K(5) is bonded in a 7-coordinate geometry to one O(14), one O(15), one O(17), one O(2), one O(23), one O(4), and one O(9) atom. The K(5)-O(14) bond length is 3.10 Å. The K(5)-O(15) bond length is 3.37 Å. The K(5)-O(17) bond length is 2.65 Å. The K(5)-O(2) bond length is 3.03 Å. The K(5)-O(23) bond length is 3.26 Å. The K(5)-O(4) bond length is 2.66 Å. The K(5)-O(9) bond length is 2.93 Å. In the sixth K site, K(6) is bonded in a 6-coordinate geometry to one O(1), one O(10), one O(16), one O(18), one O(24), and one O(3) atom. The K(6)-O(1) bond length is 2.75 Å. The K(6)-O(10) bond length is 3.02 Å. The K(6)-O(16) bond length is 2.85 Å. The K(6)-O(18) bond length is 2.76 Å. The K(6)-O(24) bond length is 2.67 Å. The K(6)-O(3) bond length is 2.71 Å. In the seventh K site, K(7) is bonded in a 10-coordinate geometry to one Mg(1), one O(11), one O(13), one O(16), one O(17), one O(19), one O(2), one O(21), one O(4), and one O(7) atom. The K(7)-Mg(1) bond length is 2.92 Å. The K(7)-O(11) bond length is 3.12 Å. The K(7)-O(13) bond length is 2.86 Å. The K(7)-O(16) bond length is 2.71 Å. The K(7)-O(17) bond length is 3.32 Å. The K(7)-O(19) bond length is 2.48 Å. The K(7)-O(2) bond length is 3.07 Å. The K(7)-O(21) bond length is 2.96 Å. The K(7)-O(4) bond length is 2.86 Å. The K(7)-O(7) bond length is 3.27 Å. In the eighth K site, K(8) is bonded in a 7-coordinate geometry to one O(1), one O(12), one O(14), one O(15), one O(20), one O(22), and one O(3) atom. The K(8)-O(1) bond length is 2.92 Å. The K(8)-O(12) bond length is 3.25 Å. The K(8)-O(14) bond length is 2.89 Å. The K(8)-O(15) bond length is 2.94 Å. The K(8)-O(20) bond length is 2.82 Å. The K(8)-O(22) bond length is 2.66 Å. The K(8)-O(3) bond length is 2.88 Å. Mg(1) is bonded in a distorted see-saw-like geometry to one K(7), one O(13), one O(2), one O(21), and one O(23) atom. The Mg(1)-O(13) bond length is 2.00 Å. The Mg(1)-O(2) bond length is 1.98 Å. The Mg(1)-O(21) bond length is 2.02 Å. The Mg(1)-O(23) bond length is 1.99 Å. There are eight inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(1), one O(13), one O(5), and one O(9) atom to form corner-sharing SiO4 tetrahedra. The Si(1)-O(1) bond length is 1.64 Å. The Si(1)-O(13) bond length is 1.61 Å. The Si(1)-O(5) bond length is 1.68 Å. The Si(1)-O(9) bond length is 1.68 Å. In the second Si site, Si(2) is bonded to one O(10), one O(14), one O(2), and one O(6) atom to form corner-sharing SiO4 tetrahedra. The Si(2)-O(10) bond length is 1.69 Å. The Si(2)-O(14) bond length is 1.61 Å. The Si(2)-O(2) bond length is 1.61 Å. The Si(2)-O(6) bond length is 1.68 Å. In the third Si site, Si(3) is bonded to one O(11), one O(15), one O(3), and one O(7) atom to form SiO4 tetrahedra that share  a cornercorner with one Si(5)O4 tetrahedra,  a cornercorner with one Si(7)O4 tetrahedra, and  an edgeedge with one K(4)O7 pentagonal bipyramid. The Si(3)-O(11) bond length is 1.65 Å. The Si(3)-O(15) bond length is 1.62 Å. The Si(3)-O(3) bond length is 1.62 Å. The Si(3)-O(7) bond length is 1.66 Å. In the fourth Si site, Si(4) is bonded to one O(12), one O(16), one O(4), and one O(8) atom to form SiO4 tetrahedra that share corners with two equivalent K(4)O7 pentagonal bipyramids,  a cornercorner with one Si(6)O4 tetrahedra, and  a cornercorner with one Si(8)O4 tetrahedra. The Si(4)-O(12) bond length is 1.66 Å. The Si(4)-O(16) bond length is 1.62 Å. The Si(4)-O(4) bond length is 1.62 Å. The Si(4)-O(8) bond length is 1.66 Å. In the fifth Si site, Si(5) is bonded to one O(11), one O(17), one O(21), and one O(5) atom to form SiO4 tetrahedra that share  a cornercorner with one K(4)O7 pentagonal bipyramid,  a cornercorner with one Si(1)O4 tetrahedra, and  a cornercorner with one Si(3)O4 tetrahedra. The Si(5)-O(11) bond length is 1.66 Å. The Si(5)-O(17) bond length is 1.63 Å. The Si(5)-O(21) bond length is 1.62 Å. The Si(5)-O(5) bond length is 1.68 Å. In the sixth Si site, Si(6) is bonded to one O(12), one O(18), one O(22), and one O(6) atom to form SiO4 tetrahedra that share  a cornercorner with one Si(2)O4 tetrahedra,  a cornercorner with one Si(4)O4 tetrahedra, and  an edgeedge with one K(4)O7 pentagonal bipyramid. The Si(6)-O(12) bond length is 1.66 Å. The Si(6)-O(18) bond length is 1.62 Å. The Si(6)-O(22) bond length is 1.62 Å. The Si(6)-O(6) bond length is 1.66 Å. In the seventh Si site, Si(7) is bonded to one O(19), one O(23), one O(7), and one O(9) atom to form SiO4 tetrahedra that share  a cornercorner with one K(4)O7 pentagonal bipyramid,  a cornercorner with one Si(1)O4 tetrahedra, and  a cornercorner with one Si(3)O4 tetrahedra. The Si(7)-O(19) bond length is 1.61 Å. The Si(7)-O(23) bond length is 1.63 Å. The Si(7)-O(7) bond length is 1.70 Å. The Si(7)-O(9) bond length is 1.69 Å. In the eighth Si site, Si(8) is bonded to one O(10), one O(20), one O(24), and one O(8) atom to form SiO4 tetrahedra that share  a cornercorner with one K(4)O7 pentagonal bipyramid,  a cornercorner with one Si(2)O4 tetrahedra, and  a cornercorner with one Si(4)O4 tetrahedra. The Si(8)-O(10) bond length is 1.66 Å. The Si(8)-O(20) bond length is 1.62 Å. The Si(8)-O(24) bond length is 1.64 Å. The Si(8)-O(8) bond length is 1.67 Å. There are twenty-four inequivalent O sites. In the first O site, O(1) is bonded in a distorted single-bond geometry to one K(2), one K(6), one K(8), and one Si(1) atom. In the second O site, O(2) is bonded in a 2-coordinate geometry to one K(5), one K(7), one Mg(1), and one Si(2) atom. In the third O site, O(3) is bonded in a distorted single-bond geometry to one K(4), one K(6), one K(8), and one Si(3) atom. In the fourth O site, O(4) is bonded in a 1-coordinate geometry to one K(5), one K(7), and one Si(4) atom. In the fifth O site, O(5) is bonded in a distorted bent 120 degrees geometry to one K(2), one Si(1), and one Si(5) atom. In the sixth O site, O(6) is bonded in a 2-coordinate geometry to one K(1), one Si(2), and one Si(6) atom. In the seventh O site, O(7) is bonded in a 2-coordinate geometry to one K(4), one K(7), one Si(3), and one Si(7) atom. In the eighth O site, O(8) is bonded in a 2-coordinate geometry to one K(3), one Si(4), and one Si(8) atom. In the ninth O site, O(9) is bonded in a distorted bent 120 degrees geometry to one K(5), one Si(1), and one Si(7) atom. In the tenth O site, O(10) is bonded in a 2-coordinate geometry to one K(2), one K(6), one Si(2), and one Si(8) atom. In the eleventh O site, O(11) is bonded in a bent 150 degrees geometry to one K(7), one Si(3), and one Si(5) atom. In the twelfth O site, O(12) is bonded in a distorted bent 150 degrees geometry to one K(4), one K(8), one Si(4), and one Si(6) atom. In the thirteenth O site, O(13) is bonded in a 2-coordinate geometry to one K(1), one K(7), one Mg(1), and one Si(1) atom. In the fourteenth O site, O(14) is bonded in a distorted single-bond geometry to one K(1), one K(2), one K(5), one K(8), and one Si(2) atom. In the fifteenth O site, O(15) is bonded in a distorted single-bond geometry to one K(3), one K(5), one K(8), and one Si(3) atom. In the sixteenth O site, O(16) is bonded in a distorted single-bond geometry to one K(3), one K(4), one K(6), one K(7), and one Si(4) atom. In the seventeenth O site, O(17) is bonded in a 1-coordinate geometry to one K(1), one K(3), one K(5), one K(7), and one Si(5) atom. In the eighteenth O site, O(18) is bonded in a distorted single-bond geometry to one K(2), one K(4), one K(6), and one Si(6) atom. In the nineteenth O site, O(19) is bonded in a 3-coordinate geometry to one K(3), one K(7), and one Si(7) atom. In the twentieth O site, O(20) is bonded in a distorted single-bond geometry to one K(2), one K(4), one K(8), and one Si(8) atom. In the twenty-first O site, O(21) is bonded in a 2-coordinate geometry to one K(4), one K(7), one Mg(1), and one Si(5) atom. In the twenty-second O site, O(22) is bonded in a 1-coordinate geometry to one K(3), one K(8), and one Si(6) atom. In the twenty-third O site, O(23) is bonded in a 2-coordinate geometry to one K(2), one K(5), one Mg(1), and one Si(7) atom. In the twenty-fourth O site, O(24) is bonded in a distorted single-bond geometry to one K(1), one K(6), and one Si(8) atom.