Ba2SrCa3Mg2(SiO4)4 crystallizes in the triclinic P1 space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded to one O(1), one O(11), one O(13), one O(16), one O(4), one O(6), one O(8), one O(9), two equivalent O(2), and two equivalent O(3) atoms to form BaO12 cuboctahedra that share edges with two equivalent Ba(1)O12 cuboctahedra, edges with four equivalent Ba(2)O12 cuboctahedra,  an edgeedge with one Si(1)O4 tetrahedra,  an edgeedge with one Si(4)O4 tetrahedra, edges with two equivalent Si(2)O4 tetrahedra, edges with two equivalent Si(3)O4 tetrahedra, and faces with two equivalent Mg(1)O6 octahedra. In the second Ba site, Ba(2) is bonded to one O(10), one O(12), one O(14), one O(15), one O(2), one O(3), one O(5), one O(7), two equivalent O(1), and two equivalent O(4) atoms to form BaO12 cuboctahedra that share edges with two equivalent Ba(2)O12 cuboctahedra, edges with four equivalent Ba(1)O12 cuboctahedra,  an edgeedge with one Si(2)O4 tetrahedra,  an edgeedge with one Si(3)O4 tetrahedra, edges with two equivalent Si(1)O4 tetrahedra, edges with two equivalent Si(4)O4 tetrahedra, and faces with two equivalent Mg(2)O6 octahedra. Sr(1) is bonded in a 10-coordinate geometry to one O(1), one O(11), one O(12), one O(13), one O(14), one O(5), one O(7), one O(9), and two equivalent O(15) atoms. There are three inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a 4-coordinate geometry to one O(11), one O(12), one O(13), one O(14), one O(16), and one O(2) atom. In the second Ca site, Ca(2) is bonded in a 4-coordinate geometry to one O(11), one O(13), one O(15), one O(3), one O(6), one O(7), and one O(9) atom. In the third Ca site, Ca(3) is bonded in a 4-coordinate geometry to one O(10), one O(12), one O(14), one O(4), one O(5), and one O(8) atom. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to one O(11), one O(13), one O(16), one O(6), one O(8), and one O(9) atom to form MgO6 octahedra that share  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(4)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, corners with two equivalent Si(3)O4 tetrahedra, and faces with two equivalent Ba(1)O12 cuboctahedra. In the second Mg site, Mg(2) is bonded to one O(10), one O(12), one O(14), one O(15), one O(5), and one O(7) atom to form MgO6 octahedra that share  a cornercorner with one Si(2)O4 tetrahedra,  a cornercorner with one Si(3)O4 tetrahedra, corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Si(4)O4 tetrahedra, and faces with two equivalent Ba(2)O12 cuboctahedra. There are four inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(1), one O(5), one O(7), and one O(9) atom to form SiO4 tetrahedra that share  a cornercorner with one Mg(1)O6 octahedra, corners with two equivalent Mg(2)O6 octahedra,  an edgeedge with one Ba(1)O12 cuboctahedra, and edges with two equivalent Ba(2)O12 cuboctahedra. The corner-sharing octahedral tilt angles are 23°. In the second Si site, Si(2) is bonded to one O(10), one O(2), one O(6), and one O(8) atom to form SiO4 tetrahedra that share  a cornercorner with one Mg(2)O6 octahedra, corners with two equivalent Mg(1)O6 octahedra,  an edgeedge with one Ba(2)O12 cuboctahedra, and edges with two equivalent Ba(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles are 23°. In the third Si site, Si(3) is bonded to one O(11), one O(13), one O(15), and one O(3) atom to form SiO4 tetrahedra that share  a cornercorner with one Mg(2)O6 octahedra, corners with two equivalent Mg(1)O6 octahedra,  an edgeedge with one Ba(2)O12 cuboctahedra, and edges with two equivalent Ba(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 17-20°. In the fourth Si site, Si(4) is bonded to one O(12), one O(14), one O(16), and one O(4) atom to form SiO4 tetrahedra that share  a cornercorner with one Mg(1)O6 octahedra, corners with two equivalent Mg(2)O6 octahedra,  an edgeedge with one Ba(1)O12 cuboctahedra, and edges with two equivalent Ba(2)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 19-22°. There are sixteen inequivalent O sites. In the first O site, O(1) is bonded in a distorted linear geometry to one Ba(1), two equivalent Ba(2), one Sr(1), and one Si(1) atom. In the second O site, O(2) is bonded in a distorted linear geometry to one Ba(2), two equivalent Ba(1), one Ca(1), and one Si(2) atom. In the third O site, O(3) is bonded in a distorted linear geometry to one Ba(2), two equivalent Ba(1), one Ca(2), and one Si(3) atom. In the fourth O site, O(4) is bonded in a distorted linear geometry to one Ba(1), two equivalent Ba(2), one Ca(3), and one Si(4) atom. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to one Ba(2), one Sr(1), one Ca(3), one Mg(2), and one Si(1) atom. In the sixth O site, O(6) is bonded in a 3-coordinate geometry to one Ba(1), one Ca(2), one Mg(1), and one Si(2) atom. In the seventh O site, O(7) is bonded in a 3-coordinate geometry to one Ba(2), one Sr(1), one Ca(2), one Mg(2), and one Si(1) atom. In the eighth O site, O(8) is bonded in a 3-coordinate geometry to one Ba(1), one Ca(3), one Mg(1), and one Si(2) atom. In the ninth O site, O(9) is bonded in a 3-coordinate geometry to one Ba(1), one Sr(1), one Ca(2), one Mg(1), and one Si(1) atom. In the tenth O site, O(10) is bonded in a 3-coordinate geometry to one Ba(2), one Ca(3), one Mg(2), and one Si(2) atom. In the eleventh O site, O(11) is bonded in a 6-coordinate geometry to one Ba(1), one Sr(1), one Ca(1), one Ca(2), one Mg(1), and one Si(3) atom. In the twelfth O site, O(12) is bonded in a 6-coordinate geometry to one Ba(2), one Sr(1), one Ca(1), one Ca(3), one Mg(2), and one Si(4) atom. In the thirteenth O site, O(13) is bonded in a 6-coordinate geometry to one Ba(1), one Sr(1), one Ca(1), one Ca(2), one Mg(1), and one Si(3) atom. In the fourteenth O site, O(14) is bonded in a 6-coordinate geometry to one Ba(2), one Sr(1), one Ca(1), one Ca(3), one Mg(2), and one Si(4) atom. In the fifteenth O site, O(15) is bonded in a 6-coordinate geometry to one Ba(2), two equivalent Sr(1), one Ca(2), one Mg(2), and one Si(3) atom. In the sixteenth O site, O(16) is bonded in a 2-coordinate geometry to one Ba(1), one Ca(1), one Mg(1), and one Si(4) atom.
Ba2SrCa3Mg2(SiO4)4 crystallizes in the triclinic P1 space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded to one O(1), one O(11), one O(13), one O(16), one O(4), one O(6), one O(8), one O(9), two equivalent O(2), and two equivalent O(3) atoms to form BaO12 cuboctahedra that share edges with two equivalent Ba(1)O12 cuboctahedra, edges with four equivalent Ba(2)O12 cuboctahedra,  an edgeedge with one Si(1)O4 tetrahedra,  an edgeedge with one Si(4)O4 tetrahedra, edges with two equivalent Si(2)O4 tetrahedra, edges with two equivalent Si(3)O4 tetrahedra, and faces with two equivalent Mg(1)O6 octahedra. The Ba(1)-O(1) bond length is 3.19 Å. The Ba(1)-O(11) bond length is 2.81 Å. The Ba(1)-O(13) bond length is 2.79 Å. The Ba(1)-O(16) bond length is 2.79 Å. The Ba(1)-O(4) bond length is 3.17 Å. The Ba(1)-O(6) bond length is 2.81 Å. The Ba(1)-O(8) bond length is 2.82 Å. The Ba(1)-O(9) bond length is 2.83 Å. Both Ba(1)-O(2) bond lengths are 3.18 Å. Both Ba(1)-O(3) bond lengths are 3.18 Å. In the second Ba site, Ba(2) is bonded to one O(10), one O(12), one O(14), one O(15), one O(2), one O(3), one O(5), one O(7), two equivalent O(1), and two equivalent O(4) atoms to form BaO12 cuboctahedra that share edges with two equivalent Ba(2)O12 cuboctahedra, edges with four equivalent Ba(1)O12 cuboctahedra,  an edgeedge with one Si(2)O4 tetrahedra,  an edgeedge with one Si(3)O4 tetrahedra, edges with two equivalent Si(1)O4 tetrahedra, edges with two equivalent Si(4)O4 tetrahedra, and faces with two equivalent Mg(2)O6 octahedra. The Ba(2)-O(10) bond length is 2.81 Å. The Ba(2)-O(12) bond length is 2.81 Å. The Ba(2)-O(14) bond length is 2.83 Å. The Ba(2)-O(15) bond length is 2.82 Å. The Ba(2)-O(2) bond length is 3.17 Å. The Ba(2)-O(3) bond length is 3.19 Å. The Ba(2)-O(5) bond length is 2.83 Å. The Ba(2)-O(7) bond length is 2.82 Å. There is one shorter (3.18 Å) and one longer (3.19 Å) Ba(2)-O(1) bond length. Both Ba(2)-O(4) bond lengths are 3.18 Å. Sr(1) is bonded in a 10-coordinate geometry to one O(1), one O(11), one O(12), one O(13), one O(14), one O(5), one O(7), one O(9), and two equivalent O(15) atoms. The Sr(1)-O(1) bond length is 2.35 Å. The Sr(1)-O(11) bond length is 3.03 Å. The Sr(1)-O(12) bond length is 2.56 Å. The Sr(1)-O(13) bond length is 2.57 Å. The Sr(1)-O(14) bond length is 3.06 Å. The Sr(1)-O(5) bond length is 2.79 Å. The Sr(1)-O(7) bond length is 2.78 Å. The Sr(1)-O(9) bond length is 2.78 Å. There is one shorter (2.58 Å) and one longer (2.93 Å) Sr(1)-O(15) bond length. There are three inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a 4-coordinate geometry to one O(11), one O(12), one O(13), one O(14), one O(16), and one O(2) atom. The Ca(1)-O(11) bond length is 2.49 Å. The Ca(1)-O(12) bond length is 2.95 Å. The Ca(1)-O(13) bond length is 2.92 Å. The Ca(1)-O(14) bond length is 2.48 Å. The Ca(1)-O(16) bond length is 2.45 Å. The Ca(1)-O(2) bond length is 2.27 Å. In the second Ca site, Ca(2) is bonded in a 4-coordinate geometry to one O(11), one O(13), one O(15), one O(3), one O(6), one O(7), and one O(9) atom. The Ca(2)-O(11) bond length is 2.84 Å. The Ca(2)-O(13) bond length is 2.84 Å. The Ca(2)-O(15) bond length is 2.82 Å. The Ca(2)-O(3) bond length is 2.27 Å. The Ca(2)-O(6) bond length is 2.43 Å. The Ca(2)-O(7) bond length is 2.46 Å. The Ca(2)-O(9) bond length is 2.45 Å. In the third Ca site, Ca(3) is bonded in a 4-coordinate geometry to one O(10), one O(12), one O(14), one O(4), one O(5), and one O(8) atom. The Ca(3)-O(10) bond length is 2.44 Å. The Ca(3)-O(12) bond length is 2.83 Å. The Ca(3)-O(14) bond length is 2.82 Å. The Ca(3)-O(4) bond length is 2.28 Å. The Ca(3)-O(5) bond length is 2.45 Å. The Ca(3)-O(8) bond length is 2.43 Å. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to one O(11), one O(13), one O(16), one O(6), one O(8), and one O(9) atom to form MgO6 octahedra that share  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(4)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, corners with two equivalent Si(3)O4 tetrahedra, and faces with two equivalent Ba(1)O12 cuboctahedra. The Mg(1)-O(11) bond length is 2.10 Å. The Mg(1)-O(13) bond length is 2.09 Å. The Mg(1)-O(16) bond length is 2.08 Å. The Mg(1)-O(6) bond length is 2.11 Å. The Mg(1)-O(8) bond length is 2.11 Å. The Mg(1)-O(9) bond length is 2.12 Å. In the second Mg site, Mg(2) is bonded to one O(10), one O(12), one O(14), one O(15), one O(5), and one O(7) atom to form MgO6 octahedra that share  a cornercorner with one Si(2)O4 tetrahedra,  a cornercorner with one Si(3)O4 tetrahedra, corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Si(4)O4 tetrahedra, and faces with two equivalent Ba(2)O12 cuboctahedra. The Mg(2)-O(10) bond length is 2.10 Å. The Mg(2)-O(12) bond length is 2.09 Å. The Mg(2)-O(14) bond length is 2.11 Å. The Mg(2)-O(15) bond length is 2.12 Å. The Mg(2)-O(5) bond length is 2.11 Å. The Mg(2)-O(7) bond length is 2.12 Å. There are four inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(1), one O(5), one O(7), and one O(9) atom to form SiO4 tetrahedra that share  a cornercorner with one Mg(1)O6 octahedra, corners with two equivalent Mg(2)O6 octahedra,  an edgeedge with one Ba(1)O12 cuboctahedra, and edges with two equivalent Ba(2)O12 cuboctahedra. The corner-sharing octahedral tilt angles are 23°. The Si(1)-O(1) bond length is 1.61 Å. The Si(1)-O(5) bond length is 1.66 Å. The Si(1)-O(7) bond length is 1.66 Å. The Si(1)-O(9) bond length is 1.66 Å. In the second Si site, Si(2) is bonded to one O(10), one O(2), one O(6), and one O(8) atom to form SiO4 tetrahedra that share  a cornercorner with one Mg(2)O6 octahedra, corners with two equivalent Mg(1)O6 octahedra,  an edgeedge with one Ba(2)O12 cuboctahedra, and edges with two equivalent Ba(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles are 23°. The Si(2)-O(10) bond length is 1.66 Å. The Si(2)-O(2) bond length is 1.62 Å. The Si(2)-O(6) bond length is 1.66 Å. The Si(2)-O(8) bond length is 1.66 Å. In the third Si site, Si(3) is bonded to one O(11), one O(13), one O(15), and one O(3) atom to form SiO4 tetrahedra that share  a cornercorner with one Mg(2)O6 octahedra, corners with two equivalent Mg(1)O6 octahedra,  an edgeedge with one Ba(2)O12 cuboctahedra, and edges with two equivalent Ba(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 17-20°. The Si(3)-O(11) bond length is 1.66 Å. The Si(3)-O(13) bond length is 1.65 Å. The Si(3)-O(15) bond length is 1.66 Å. The Si(3)-O(3) bond length is 1.62 Å. In the fourth Si site, Si(4) is bonded to one O(12), one O(14), one O(16), and one O(4) atom to form SiO4 tetrahedra that share  a cornercorner with one Mg(1)O6 octahedra, corners with two equivalent Mg(2)O6 octahedra,  an edgeedge with one Ba(1)O12 cuboctahedra, and edges with two equivalent Ba(2)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 19-22°. The Si(4)-O(12) bond length is 1.66 Å. The Si(4)-O(14) bond length is 1.66 Å. The Si(4)-O(16) bond length is 1.66 Å. The Si(4)-O(4) bond length is 1.62 Å. There are sixteen inequivalent O sites. In the first O site, O(1) is bonded in a distorted linear geometry to one Ba(1), two equivalent Ba(2), one Sr(1), and one Si(1) atom. In the second O site, O(2) is bonded in a distorted linear geometry to one Ba(2), two equivalent Ba(1), one Ca(1), and one Si(2) atom. In the third O site, O(3) is bonded in a distorted linear geometry to one Ba(2), two equivalent Ba(1), one Ca(2), and one Si(3) atom. In the fourth O site, O(4) is bonded in a distorted linear geometry to one Ba(1), two equivalent Ba(2), one Ca(3), and one Si(4) atom. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to one Ba(2), one Sr(1), one Ca(3), one Mg(2), and one Si(1) atom. In the sixth O site, O(6) is bonded in a 3-coordinate geometry to one Ba(1), one Ca(2), one Mg(1), and one Si(2) atom. In the seventh O site, O(7) is bonded in a 3-coordinate geometry to one Ba(2), one Sr(1), one Ca(2), one Mg(2), and one Si(1) atom. In the eighth O site, O(8) is bonded in a 3-coordinate geometry to one Ba(1), one Ca(3), one Mg(1), and one Si(2) atom. In the ninth O site, O(9) is bonded in a 3-coordinate geometry to one Ba(1), one Sr(1), one Ca(2), one Mg(1), and one Si(1) atom. In the tenth O site, O(10) is bonded in a 3-coordinate geometry to one Ba(2), one Ca(3), one Mg(2), and one Si(2) atom. In the eleventh O site, O(11) is bonded in a 6-coordinate geometry to one Ba(1), one Sr(1), one Ca(1), one Ca(2), one Mg(1), and one Si(3) atom. In the twelfth O site, O(12) is bonded in a 6-coordinate geometry to one Ba(2), one Sr(1), one Ca(1), one Ca(3), one Mg(2), and one Si(4) atom. In the thirteenth O site, O(13) is bonded in a 6-coordinate geometry to one Ba(1), one Sr(1), one Ca(1), one Ca(2), one Mg(1), and one Si(3) atom. In the fourteenth O site, O(14) is bonded in a 6-coordinate geometry to one Ba(2), one Sr(1), one Ca(1), one Ca(3), one Mg(2), and one Si(4) atom. In the fifteenth O site, O(15) is bonded in a 6-coordinate geometry to one Ba(2), two equivalent Sr(1), one Ca(2), one Mg(2), and one Si(3) atom. In the sixteenth O site, O(16) is bonded in a 2-coordinate geometry to one Ba(1), one Ca(1), one Mg(1), and one Si(4) atom.