Sr4CaSm2Ta2O12 crystallizes in the triclinic P1 space group. There are four inequivalent Sr sites. In the first Sr site, Sr(1) is bonded in a 4-coordinate geometry to one O(1), one O(12), one O(3), and one O(7) atom. In the second Sr site, Sr(2) is bonded in a 9-coordinate geometry to one O(10), one O(11), one O(12), one O(2), one O(5), one O(6), one O(8), and two equivalent O(4) atoms. In the third Sr site, Sr(3) is bonded in a 6-coordinate geometry to one O(1), one O(10), one O(3), one O(6), one O(7), and one O(9) atom. In the fourth Sr site, Sr(4) is bonded in a 8-coordinate geometry to one O(10), one O(11), one O(12), one O(2), one O(4), one O(5), one O(8), and one O(9) atom. Ca(1) is bonded in a 5-coordinate geometry to one O(1), one O(10), one O(3), one O(5), and one O(6) atom. There are two inequivalent Sm sites. In the first Sm site, Sm(1) is bonded to one O(11), one O(12), one O(2), one O(7), and one O(8) atom to form SmO5 square pyramids that share  a cornercorner with one Ta(1)O6 octahedra and corners with four equivalent Ta(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 7-37°. In the second Sm site, Sm(2) is bonded to one O(10), one O(4), one O(5), one O(6), and one O(9) atom to form distorted SmO5 square pyramids that share  a cornercorner with one Ta(2)O6 octahedra and corners with four equivalent Ta(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 16-47°. There are two inequivalent Ta sites. In the first Ta site, Ta(1) is bonded to one O(1), one O(10), one O(2), one O(5), one O(6), and one O(9) atom to form TaO6 octahedra that share  a cornercorner with one Sm(1)O5 square pyramid and corners with four equivalent Sm(2)O5 square pyramids. In the second Ta site, Ta(2) is bonded to one O(11), one O(12), one O(3), one O(4), one O(7), and one O(8) atom to form TaO6 octahedra that share  a cornercorner with one Sm(2)O5 square pyramid and corners with four equivalent Sm(1)O5 square pyramids. There are twelve inequivalent O sites. In the first O site, O(1) is bonded in a distorted rectangular see-saw-like geometry to one Sr(1), one Sr(3), one Ca(1), and one Ta(1) atom. In the second O site, O(2) is bonded in a 4-coordinate geometry to one Sr(2), one Sr(4), one Sm(1), and one Ta(1) atom. In the third O site, O(3) is bonded to one Sr(1), one Sr(3), one Ca(1), and one Ta(2) atom to form distorted edge-sharing OSr2CaTa trigonal pyramids. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Sr(4), two equivalent Sr(2), one Sm(2), and one Ta(2) atom. In the fifth O site, O(5) is bonded in a 5-coordinate geometry to one Sr(2), one Sr(4), one Ca(1), one Sm(2), and one Ta(1) atom. In the sixth O site, O(6) is bonded in a 5-coordinate geometry to one Sr(2), one Sr(3), one Ca(1), one Sm(2), and one Ta(1) atom. In the seventh O site, O(7) is bonded in a 4-coordinate geometry to one Sr(1), one Sr(3), one Sm(1), and one Ta(2) atom. In the eighth O site, O(8) is bonded in a 4-coordinate geometry to one Sr(2), one Sr(4), one Sm(1), and one Ta(2) atom. In the ninth O site, O(9) is bonded in a 3-coordinate geometry to one Sr(3), one Sr(4), one Sm(2), and one Ta(1) atom. In the tenth O site, O(10) is bonded in a 6-coordinate geometry to one Sr(2), one Sr(3), one Sr(4), one Ca(1), one Sm(2), and one Ta(1) atom. In the eleventh O site, O(11) is bonded in a 4-coordinate geometry to one Sr(2), one Sr(4), one Sm(1), and one Ta(2) atom. In the twelfth O site, O(12) is bonded to one Sr(1), one Sr(2), one Sr(4), one Sm(1), and one Ta(2) atom to form distorted edge-sharing OSr3SmTa square pyramids.
Sr4CaSm2Ta2O12 crystallizes in the triclinic P1 space group. There are four inequivalent Sr sites. In the first Sr site, Sr(1) is bonded in a 4-coordinate geometry to one O(1), one O(12), one O(3), and one O(7) atom. The Sr(1)-O(1) bond length is 2.44 Å. The Sr(1)-O(12) bond length is 2.48 Å. The Sr(1)-O(3) bond length is 2.41 Å. The Sr(1)-O(7) bond length is 2.51 Å. In the second Sr site, Sr(2) is bonded in a 9-coordinate geometry to one O(10), one O(11), one O(12), one O(2), one O(5), one O(6), one O(8), and two equivalent O(4) atoms. The Sr(2)-O(10) bond length is 3.11 Å. The Sr(2)-O(11) bond length is 2.65 Å. The Sr(2)-O(12) bond length is 2.68 Å. The Sr(2)-O(2) bond length is 2.62 Å. The Sr(2)-O(5) bond length is 2.57 Å. The Sr(2)-O(6) bond length is 2.77 Å. The Sr(2)-O(8) bond length is 2.59 Å. There is one shorter (2.86 Å) and one longer (3.23 Å) Sr(2)-O(4) bond length. In the third Sr site, Sr(3) is bonded in a 6-coordinate geometry to one O(1), one O(10), one O(3), one O(6), one O(7), and one O(9) atom. The Sr(3)-O(1) bond length is 2.36 Å. The Sr(3)-O(10) bond length is 2.75 Å. The Sr(3)-O(3) bond length is 2.54 Å. The Sr(3)-O(6) bond length is 2.75 Å. The Sr(3)-O(7) bond length is 2.63 Å. The Sr(3)-O(9) bond length is 2.59 Å. In the fourth Sr site, Sr(4) is bonded in a 8-coordinate geometry to one O(10), one O(11), one O(12), one O(2), one O(4), one O(5), one O(8), and one O(9) atom. The Sr(4)-O(10) bond length is 2.74 Å. The Sr(4)-O(11) bond length is 2.73 Å. The Sr(4)-O(12) bond length is 2.90 Å. The Sr(4)-O(2) bond length is 2.73 Å. The Sr(4)-O(4) bond length is 2.53 Å. The Sr(4)-O(5) bond length is 3.06 Å. The Sr(4)-O(8) bond length is 2.56 Å. The Sr(4)-O(9) bond length is 3.07 Å. Ca(1) is bonded in a 5-coordinate geometry to one O(1), one O(10), one O(3), one O(5), and one O(6) atom. The Ca(1)-O(1) bond length is 2.25 Å. The Ca(1)-O(10) bond length is 2.72 Å. The Ca(1)-O(3) bond length is 2.44 Å. The Ca(1)-O(5) bond length is 2.55 Å. The Ca(1)-O(6) bond length is 2.41 Å. There are two inequivalent Sm sites. In the first Sm site, Sm(1) is bonded to one O(11), one O(12), one O(2), one O(7), and one O(8) atom to form SmO5 square pyramids that share  a cornercorner with one Ta(1)O6 octahedra and corners with four equivalent Ta(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 7-37°. The Sm(1)-O(11) bond length is 2.34 Å. The Sm(1)-O(12) bond length is 2.42 Å. The Sm(1)-O(2) bond length is 2.28 Å. The Sm(1)-O(7) bond length is 2.34 Å. The Sm(1)-O(8) bond length is 2.29 Å. In the second Sm site, Sm(2) is bonded to one O(10), one O(4), one O(5), one O(6), and one O(9) atom to form distorted SmO5 square pyramids that share  a cornercorner with one Ta(2)O6 octahedra and corners with four equivalent Ta(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 16-47°. The Sm(2)-O(10) bond length is 2.30 Å. The Sm(2)-O(4) bond length is 2.21 Å. The Sm(2)-O(5) bond length is 2.27 Å. The Sm(2)-O(6) bond length is 2.62 Å. The Sm(2)-O(9) bond length is 2.29 Å. There are two inequivalent Ta sites. In the first Ta site, Ta(1) is bonded to one O(1), one O(10), one O(2), one O(5), one O(6), and one O(9) atom to form TaO6 octahedra that share  a cornercorner with one Sm(1)O5 square pyramid and corners with four equivalent Sm(2)O5 square pyramids. The Ta(1)-O(1) bond length is 2.01 Å. The Ta(1)-O(10) bond length is 2.09 Å. The Ta(1)-O(2) bond length is 1.99 Å. The Ta(1)-O(5) bond length is 2.05 Å. The Ta(1)-O(6) bond length is 2.06 Å. The Ta(1)-O(9) bond length is 1.97 Å. In the second Ta site, Ta(2) is bonded to one O(11), one O(12), one O(3), one O(4), one O(7), and one O(8) atom to form TaO6 octahedra that share  a cornercorner with one Sm(2)O5 square pyramid and corners with four equivalent Sm(1)O5 square pyramids. The Ta(2)-O(11) bond length is 2.00 Å. The Ta(2)-O(12) bond length is 2.12 Å. The Ta(2)-O(3) bond length is 1.97 Å. The Ta(2)-O(4) bond length is 2.06 Å. The Ta(2)-O(7) bond length is 2.03 Å. The Ta(2)-O(8) bond length is 2.02 Å. There are twelve inequivalent O sites. In the first O site, O(1) is bonded in a distorted rectangular see-saw-like geometry to one Sr(1), one Sr(3), one Ca(1), and one Ta(1) atom. In the second O site, O(2) is bonded in a 4-coordinate geometry to one Sr(2), one Sr(4), one Sm(1), and one Ta(1) atom. In the third O site, O(3) is bonded to one Sr(1), one Sr(3), one Ca(1), and one Ta(2) atom to form distorted edge-sharing OSr2CaTa trigonal pyramids. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Sr(4), two equivalent Sr(2), one Sm(2), and one Ta(2) atom. In the fifth O site, O(5) is bonded in a 5-coordinate geometry to one Sr(2), one Sr(4), one Ca(1), one Sm(2), and one Ta(1) atom. In the sixth O site, O(6) is bonded in a 5-coordinate geometry to one Sr(2), one Sr(3), one Ca(1), one Sm(2), and one Ta(1) atom. In the seventh O site, O(7) is bonded in a 4-coordinate geometry to one Sr(1), one Sr(3), one Sm(1), and one Ta(2) atom. In the eighth O site, O(8) is bonded in a 4-coordinate geometry to one Sr(2), one Sr(4), one Sm(1), and one Ta(2) atom. In the ninth O site, O(9) is bonded in a 3-coordinate geometry to one Sr(3), one Sr(4), one Sm(2), and one Ta(1) atom. In the tenth O site, O(10) is bonded in a 6-coordinate geometry to one Sr(2), one Sr(3), one Sr(4), one Ca(1), one Sm(2), and one Ta(1) atom. In the eleventh O site, O(11) is bonded in a 4-coordinate geometry to one Sr(2), one Sr(4), one Sm(1), and one Ta(2) atom. In the twelfth O site, O(12) is bonded to one Sr(1), one Sr(2), one Sr(4), one Sm(1), and one Ta(2) atom to form distorted edge-sharing OSr3SmTa square pyramids.