BaFe2(PO4)2 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(10), one O(12), one O(13), one O(16), one O(3), one O(6), one O(7), two equivalent O(2), and two equivalent O(4) atoms to form BaO12 cuboctahedra that share  a cornercorner with one Fe(1)O6 octahedra,  a cornercorner with one Fe(4)O6 octahedra, corners with two equivalent Fe(2)O6 octahedra, corners with two equivalent Fe(3)O6 octahedra, edges with two equivalent Ba(1)O12 cuboctahedra, edges with four equivalent Ba(2)O12 cuboctahedra,  an edgeedge with one P(1)O4 tetrahedra,  an edgeedge with one P(3)O4 tetrahedra, edges with two equivalent P(2)O4 tetrahedra, edges with two equivalent P(4)O4 tetrahedra,  a faceface with one Fe(1)O6 octahedra, and  a faceface with one Fe(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 51-52°. In the second Ba site, Ba(2) is bonded to one O(11), one O(14), one O(15), one O(2), one O(4), one O(5), one O(8), one O(9), two equivalent O(1), and two equivalent O(3) atoms to form BaO12 cuboctahedra that share  a cornercorner with one Fe(2)O6 octahedra,  a cornercorner with one Fe(3)O6 octahedra, corners with two equivalent Fe(1)O6 octahedra, corners with two equivalent Fe(4)O6 octahedra, edges with two equivalent Ba(2)O12 cuboctahedra, edges with four equivalent Ba(1)O12 cuboctahedra,  an edgeedge with one P(2)O4 tetrahedra,  an edgeedge with one P(4)O4 tetrahedra, edges with two equivalent P(1)O4 tetrahedra, edges with two equivalent P(3)O4 tetrahedra,  a faceface with one Fe(2)O6 octahedra, and  a faceface with one Fe(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 51-52°. There are four inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(10), one O(12), one O(13), one O(16), one O(5), and one O(8) atom to form FeO6 octahedra that share  a cornercorner with one Ba(1)O12 cuboctahedra, corners with two equivalent Ba(2)O12 cuboctahedra,  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(3)O4 tetrahedra, corners with two equivalent P(2)O4 tetrahedra, corners with two equivalent P(4)O4 tetrahedra,  an edgeedge with one Fe(4)O6 octahedra, edges with two equivalent Fe(2)O6 octahedra, and  a faceface with one Ba(1)O12 cuboctahedra. In the second Fe site, Fe(2) is bonded to one O(12), one O(13), one O(15), one O(5), one O(8), and one O(9) atom to form FeO6 octahedra that share  a cornercorner with one Ba(2)O12 cuboctahedra, corners with two equivalent Ba(1)O12 cuboctahedra,  a cornercorner with one P(2)O4 tetrahedra,  a cornercorner with one P(4)O4 tetrahedra, corners with two equivalent P(1)O4 tetrahedra, corners with two equivalent P(3)O4 tetrahedra,  an edgeedge with one Fe(3)O6 octahedra, edges with two equivalent Fe(1)O6 octahedra, and  a faceface with one Ba(2)O12 cuboctahedra. In the third Fe site, Fe(3) is bonded to one O(11), one O(14), one O(15), one O(6), one O(7), and one O(9) atom to form FeO6 octahedra that share  a cornercorner with one Ba(2)O12 cuboctahedra, corners with two equivalent Ba(1)O12 cuboctahedra,  a cornercorner with one P(2)O4 tetrahedra,  a cornercorner with one P(4)O4 tetrahedra, corners with two equivalent P(1)O4 tetrahedra, corners with two equivalent P(3)O4 tetrahedra,  an edgeedge with one Fe(2)O6 octahedra, edges with two equivalent Fe(4)O6 octahedra, and  a faceface with one Ba(2)O12 cuboctahedra. In the fourth Fe site, Fe(4) is bonded to one O(10), one O(11), one O(14), one O(16), one O(6), and one O(7) atom to form FeO6 octahedra that share  a cornercorner with one Ba(1)O12 cuboctahedra, corners with two equivalent Ba(2)O12 cuboctahedra,  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(3)O4 tetrahedra, corners with two equivalent P(2)O4 tetrahedra, corners with two equivalent P(4)O4 tetrahedra,  an edgeedge with one Fe(1)O6 octahedra, edges with two equivalent Fe(3)O6 octahedra, and  a faceface with one Ba(1)O12 cuboctahedra. There are four inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(5), one O(7), and one O(9) atom to form PO4 tetrahedra that share  a cornercorner with one Fe(1)O6 octahedra,  a cornercorner with one Fe(4)O6 octahedra, corners with two equivalent Fe(2)O6 octahedra, corners with two equivalent Fe(3)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 49-54°. In the second P site, P(2) is bonded to one O(10), one O(2), one O(6), and one O(8) atom to form PO4 tetrahedra that share  a cornercorner with one Fe(2)O6 octahedra,  a cornercorner with one Fe(3)O6 octahedra, corners with two equivalent Fe(1)O6 octahedra, corners with two equivalent Fe(4)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 48-55°. In the third P site, P(3) is bonded to one O(11), one O(13), one O(15), and one O(3) atom to form PO4 tetrahedra that share  a cornercorner with one Fe(1)O6 octahedra,  a cornercorner with one Fe(4)O6 octahedra, corners with two equivalent Fe(2)O6 octahedra, corners with two equivalent Fe(3)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 47-55°. In the fourth P site, P(4) is bonded to one O(12), one O(14), one O(16), and one O(4) atom to form PO4 tetrahedra that share  a cornercorner with one Fe(2)O6 octahedra,  a cornercorner with one Fe(3)O6 octahedra, corners with two equivalent Fe(1)O6 octahedra, corners with two equivalent Fe(4)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 49-54°. There are sixteen inequivalent O sites. In the first O site, O(1) is bonded in a single-bond geometry to one Ba(1), two equivalent Ba(2), and one P(1) atom. In the second O site, O(2) is bonded in a single-bond geometry to one Ba(2), two equivalent Ba(1), and one P(2) atom. In the third O site, O(3) is bonded in a single-bond geometry to one Ba(1), two equivalent Ba(2), and one P(3) atom. In the fourth O site, O(4) is bonded in a single-bond geometry to one Ba(2), two equivalent Ba(1), and one P(4) atom. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to one Ba(2), one Fe(1), one Fe(2), and one P(1) atom. In the sixth O site, O(6) is bonded in a 3-coordinate geometry to one Ba(1), one Fe(3), one Fe(4), and one P(2) atom. In the seventh O site, O(7) is bonded in a 3-coordinate geometry to one Ba(1), one Fe(3), one Fe(4), and one P(1) atom. In the eighth O site, O(8) is bonded in a 3-coordinate geometry to one Ba(2), one Fe(1), one Fe(2), and one P(2) atom. In the ninth O site, O(9) is bonded in a 3-coordinate geometry to one Ba(2), one Fe(2), one Fe(3), and one P(1) atom. In the tenth O site, O(10) is bonded in a 3-coordinate geometry to one Ba(1), one Fe(1), one Fe(4), and one P(2) atom. In the eleventh O site, O(11) is bonded in a 3-coordinate geometry to one Ba(2), one Fe(3), one Fe(4), and one P(3) atom. In the twelfth O site, O(12) is bonded in a 3-coordinate geometry to one Ba(1), one Fe(1), one Fe(2), and one P(4) atom. In the thirteenth O site, O(13) is bonded in a 3-coordinate geometry to one Ba(1), one Fe(1), one Fe(2), and one P(3) atom. In the fourteenth O site, O(14) is bonded in a 3-coordinate geometry to one Ba(2), one Fe(3), one Fe(4), and one P(4) atom. In the fifteenth O site, O(15) is bonded in a 3-coordinate geometry to one Ba(2), one Fe(2), one Fe(3), and one P(3) atom. In the sixteenth O site, O(16) is bonded in a 3-coordinate geometry to one Ba(1), one Fe(1), one Fe(4), and one P(4) atom.
BaFe2(PO4)2 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(10), one O(12), one O(13), one O(16), one O(3), one O(6), one O(7), two equivalent O(2), and two equivalent O(4) atoms to form BaO12 cuboctahedra that share  a cornercorner with one Fe(1)O6 octahedra,  a cornercorner with one Fe(4)O6 octahedra, corners with two equivalent Fe(2)O6 octahedra, corners with two equivalent Fe(3)O6 octahedra, edges with two equivalent Ba(1)O12 cuboctahedra, edges with four equivalent Ba(2)O12 cuboctahedra,  an edgeedge with one P(1)O4 tetrahedra,  an edgeedge with one P(3)O4 tetrahedra, edges with two equivalent P(2)O4 tetrahedra, edges with two equivalent P(4)O4 tetrahedra,  a faceface with one Fe(1)O6 octahedra, and  a faceface with one Fe(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 51-52°. The Ba(1)-O(1) bond length is 2.93 Å. The Ba(1)-O(10) bond length is 3.20 Å. The Ba(1)-O(12) bond length is 3.19 Å. The Ba(1)-O(13) bond length is 3.18 Å. The Ba(1)-O(16) bond length is 3.20 Å. The Ba(1)-O(3) bond length is 2.93 Å. The Ba(1)-O(6) bond length is 3.20 Å. The Ba(1)-O(7) bond length is 3.21 Å. Both Ba(1)-O(2) bond lengths are 2.93 Å. There is one shorter (2.93 Å) and one longer (2.94 Å) Ba(1)-O(4) bond length. In the second Ba site, Ba(2) is bonded to one O(11), one O(14), one O(15), one O(2), one O(4), one O(5), one O(8), one O(9), two equivalent O(1), and two equivalent O(3) atoms to form BaO12 cuboctahedra that share  a cornercorner with one Fe(2)O6 octahedra,  a cornercorner with one Fe(3)O6 octahedra, corners with two equivalent Fe(1)O6 octahedra, corners with two equivalent Fe(4)O6 octahedra, edges with two equivalent Ba(2)O12 cuboctahedra, edges with four equivalent Ba(1)O12 cuboctahedra,  an edgeedge with one P(2)O4 tetrahedra,  an edgeedge with one P(4)O4 tetrahedra, edges with two equivalent P(1)O4 tetrahedra, edges with two equivalent P(3)O4 tetrahedra,  a faceface with one Fe(2)O6 octahedra, and  a faceface with one Fe(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 51-52°. The Ba(2)-O(11) bond length is 3.19 Å. The Ba(2)-O(14) bond length is 3.21 Å. The Ba(2)-O(15) bond length is 3.20 Å. The Ba(2)-O(2) bond length is 2.93 Å. The Ba(2)-O(4) bond length is 2.93 Å. The Ba(2)-O(5) bond length is 3.19 Å. The Ba(2)-O(8) bond length is 3.18 Å. The Ba(2)-O(9) bond length is 3.20 Å. There is one shorter (2.93 Å) and one longer (2.94 Å) Ba(2)-O(1) bond length. Both Ba(2)-O(3) bond lengths are 2.93 Å. There are four inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(10), one O(12), one O(13), one O(16), one O(5), and one O(8) atom to form FeO6 octahedra that share  a cornercorner with one Ba(1)O12 cuboctahedra, corners with two equivalent Ba(2)O12 cuboctahedra,  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(3)O4 tetrahedra, corners with two equivalent P(2)O4 tetrahedra, corners with two equivalent P(4)O4 tetrahedra,  an edgeedge with one Fe(4)O6 octahedra, edges with two equivalent Fe(2)O6 octahedra, and  a faceface with one Ba(1)O12 cuboctahedra. The Fe(1)-O(10) bond length is 2.12 Å. The Fe(1)-O(12) bond length is 2.18 Å. The Fe(1)-O(13) bond length is 2.17 Å. The Fe(1)-O(16) bond length is 2.15 Å. The Fe(1)-O(5) bond length is 2.15 Å. The Fe(1)-O(8) bond length is 2.15 Å. In the second Fe site, Fe(2) is bonded to one O(12), one O(13), one O(15), one O(5), one O(8), and one O(9) atom to form FeO6 octahedra that share  a cornercorner with one Ba(2)O12 cuboctahedra, corners with two equivalent Ba(1)O12 cuboctahedra,  a cornercorner with one P(2)O4 tetrahedra,  a cornercorner with one P(4)O4 tetrahedra, corners with two equivalent P(1)O4 tetrahedra, corners with two equivalent P(3)O4 tetrahedra,  an edgeedge with one Fe(3)O6 octahedra, edges with two equivalent Fe(1)O6 octahedra, and  a faceface with one Ba(2)O12 cuboctahedra. The Fe(2)-O(12) bond length is 2.14 Å. The Fe(2)-O(13) bond length is 2.16 Å. The Fe(2)-O(15) bond length is 2.12 Å. The Fe(2)-O(5) bond length is 2.18 Å. The Fe(2)-O(8) bond length is 2.17 Å. The Fe(2)-O(9) bond length is 2.15 Å. In the third Fe site, Fe(3) is bonded to one O(11), one O(14), one O(15), one O(6), one O(7), and one O(9) atom to form FeO6 octahedra that share  a cornercorner with one Ba(2)O12 cuboctahedra, corners with two equivalent Ba(1)O12 cuboctahedra,  a cornercorner with one P(2)O4 tetrahedra,  a cornercorner with one P(4)O4 tetrahedra, corners with two equivalent P(1)O4 tetrahedra, corners with two equivalent P(3)O4 tetrahedra,  an edgeedge with one Fe(2)O6 octahedra, edges with two equivalent Fe(4)O6 octahedra, and  a faceface with one Ba(2)O12 cuboctahedra. The Fe(3)-O(11) bond length is 2.16 Å. The Fe(3)-O(14) bond length is 2.15 Å. The Fe(3)-O(15) bond length is 2.19 Å. The Fe(3)-O(6) bond length is 2.12 Å. The Fe(3)-O(7) bond length is 2.15 Å. The Fe(3)-O(9) bond length is 2.16 Å. In the fourth Fe site, Fe(4) is bonded to one O(10), one O(11), one O(14), one O(16), one O(6), and one O(7) atom to form FeO6 octahedra that share  a cornercorner with one Ba(1)O12 cuboctahedra, corners with two equivalent Ba(2)O12 cuboctahedra,  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(3)O4 tetrahedra, corners with two equivalent P(2)O4 tetrahedra, corners with two equivalent P(4)O4 tetrahedra,  an edgeedge with one Fe(1)O6 octahedra, edges with two equivalent Fe(3)O6 octahedra, and  a faceface with one Ba(1)O12 cuboctahedra. The Fe(4)-O(10) bond length is 2.19 Å. The Fe(4)-O(11) bond length is 2.13 Å. The Fe(4)-O(14) bond length is 2.14 Å. The Fe(4)-O(16) bond length is 2.16 Å. The Fe(4)-O(6) bond length is 2.18 Å. The Fe(4)-O(7) bond length is 2.14 Å. There are four inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(5), one O(7), and one O(9) atom to form PO4 tetrahedra that share  a cornercorner with one Fe(1)O6 octahedra,  a cornercorner with one Fe(4)O6 octahedra, corners with two equivalent Fe(2)O6 octahedra, corners with two equivalent Fe(3)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 49-54°. The P(1)-O(1) bond length is 1.53 Å. The P(1)-O(5) bond length is 1.57 Å. The P(1)-O(7) bond length is 1.58 Å. The P(1)-O(9) bond length is 1.57 Å. In the second P site, P(2) is bonded to one O(10), one O(2), one O(6), and one O(8) atom to form PO4 tetrahedra that share  a cornercorner with one Fe(2)O6 octahedra,  a cornercorner with one Fe(3)O6 octahedra, corners with two equivalent Fe(1)O6 octahedra, corners with two equivalent Fe(4)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 48-55°. The P(2)-O(10) bond length is 1.57 Å. The P(2)-O(2) bond length is 1.53 Å. The P(2)-O(6) bond length is 1.58 Å. The P(2)-O(8) bond length is 1.57 Å. In the third P site, P(3) is bonded to one O(11), one O(13), one O(15), and one O(3) atom to form PO4 tetrahedra that share  a cornercorner with one Fe(1)O6 octahedra,  a cornercorner with one Fe(4)O6 octahedra, corners with two equivalent Fe(2)O6 octahedra, corners with two equivalent Fe(3)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 47-55°. The P(3)-O(11) bond length is 1.58 Å. The P(3)-O(13) bond length is 1.57 Å. The P(3)-O(15) bond length is 1.57 Å. The P(3)-O(3) bond length is 1.53 Å. In the fourth P site, P(4) is bonded to one O(12), one O(14), one O(16), and one O(4) atom to form PO4 tetrahedra that share  a cornercorner with one Fe(2)O6 octahedra,  a cornercorner with one Fe(3)O6 octahedra, corners with two equivalent Fe(1)O6 octahedra, corners with two equivalent Fe(4)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 49-54°. The P(4)-O(12) bond length is 1.57 Å. The P(4)-O(14) bond length is 1.58 Å. The P(4)-O(16) bond length is 1.57 Å. The P(4)-O(4) bond length is 1.53 Å. There are sixteen inequivalent O sites. In the first O site, O(1) is bonded in a single-bond geometry to one Ba(1), two equivalent Ba(2), and one P(1) atom. In the second O site, O(2) is bonded in a single-bond geometry to one Ba(2), two equivalent Ba(1), and one P(2) atom. In the third O site, O(3) is bonded in a single-bond geometry to one Ba(1), two equivalent Ba(2), and one P(3) atom. In the fourth O site, O(4) is bonded in a single-bond geometry to one Ba(2), two equivalent Ba(1), and one P(4) atom. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to one Ba(2), one Fe(1), one Fe(2), and one P(1) atom. In the sixth O site, O(6) is bonded in a 3-coordinate geometry to one Ba(1), one Fe(3), one Fe(4), and one P(2) atom. In the seventh O site, O(7) is bonded in a 3-coordinate geometry to one Ba(1), one Fe(3), one Fe(4), and one P(1) atom. In the eighth O site, O(8) is bonded in a 3-coordinate geometry to one Ba(2), one Fe(1), one Fe(2), and one P(2) atom. In the ninth O site, O(9) is bonded in a 3-coordinate geometry to one Ba(2), one Fe(2), one Fe(3), and one P(1) atom. In the tenth O site, O(10) is bonded in a 3-coordinate geometry to one Ba(1), one Fe(1), one Fe(4), and one P(2) atom. In the eleventh O site, O(11) is bonded in a 3-coordinate geometry to one Ba(2), one Fe(3), one Fe(4), and one P(3) atom. In the twelfth O site, O(12) is bonded in a 3-coordinate geometry to one Ba(1), one Fe(1), one Fe(2), and one P(4) atom. In the thirteenth O site, O(13) is bonded in a 3-coordinate geometry to one Ba(1), one Fe(1), one Fe(2), and one P(3) atom. In the fourteenth O site, O(14) is bonded in a 3-coordinate geometry to one Ba(2), one Fe(3), one Fe(4), and one P(4) atom. In the fifteenth O site, O(15) is bonded in a 3-coordinate geometry to one Ba(2), one Fe(2), one Fe(3), and one P(3) atom. In the sixteenth O site, O(16) is bonded in a 3-coordinate geometry to one Ba(1), one Fe(1), one Fe(4), and one P(4) atom.