LiFeP2O7 crystallizes in the triclinic P1 space group. There are four inequivalent Li sites. In the first Li site, Li(1) is bonded in a distorted pentagonal planar geometry to one O(14), one O(16), one O(23), one O(8), and one O(9) atom. In the second Li site, Li(2) is bonded in a 4-coordinate geometry to one O(11), one O(25), one O(26), and one O(4) atom. In the third Li site, Li(3) is bonded in a distorted trigonal non-coplanar geometry to one O(1), one O(4), and one O(5) atom. In the fourth Li site, Li(4) is bonded in a 5-coordinate geometry to one O(15), one O(17), one O(20), one O(22), and one O(24) atom. There are four inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(12), one O(16), one O(21), one O(23), one O(26), and one O(8) atom to form FeO6 octahedra that share  a cornercorner with one Fe(2)O6 octahedra,  a cornercorner with one P(3)O4 tetrahedra,  a cornercorner with one P(4)O4 tetrahedra,  a cornercorner with one P(5)O4 tetrahedra,  a cornercorner with one P(6)O4 tetrahedra, and  an edgeedge with one P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 55°. In the second Fe site, Fe(2) is bonded to one O(1), one O(13), one O(2), one O(20), one O(21), and one O(22) atom to form FeO6 octahedra that share  a cornercorner with one Fe(1)O6 octahedra,  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(2)O4 tetrahedra,  a cornercorner with one P(3)O4 tetrahedra,  a cornercorner with one P(4)O4 tetrahedra, and corners with two equivalent P(5)O4 tetrahedra. The corner-sharing octahedral tilt angles are 55°. In the third Fe site, Fe(3) is bonded to one O(15), one O(17), one O(18), one O(19), one O(24), and one O(7) atom to form FeO6 octahedra that share  a cornercorner with one Fe(4)O6 octahedra,  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(2)O4 tetrahedra,  a cornercorner with one P(6)O4 tetrahedra,  a cornercorner with one P(8)O4 tetrahedra, and corners with two equivalent P(7)O4 tetrahedra. The corner-sharing octahedral tilt angles are 59°. In the fourth Fe site, Fe(4) is bonded to one O(11), one O(14), one O(19), one O(25), one O(28), and one O(9) atom to form FeO6 octahedra that share  a cornercorner with one Fe(3)O6 octahedra,  a cornercorner with one P(4)O4 tetrahedra,  a cornercorner with one P(6)O4 tetrahedra,  a cornercorner with one P(7)O4 tetrahedra,  a cornercorner with one P(8)O4 tetrahedra, and  an edgeedge with one P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 59°. There are eight inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(10), one O(11), and one O(19) atom to form PO4 tetrahedra that share  a cornercorner with one Fe(2)O6 octahedra,  a cornercorner with one Fe(3)O6 octahedra,  a cornercorner with one P(5)O4 tetrahedra, and  an edgeedge with one Fe(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 49-51°. In the second P site, P(2) is bonded to one O(18), one O(21), one O(26), and one O(27) atom to form PO4 tetrahedra that share  a cornercorner with one Fe(2)O6 octahedra,  a cornercorner with one Fe(3)O6 octahedra,  a cornercorner with one P(7)O4 tetrahedra, and  an edgeedge with one Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 45-50°. In the third P site, P(3) is bonded to one O(20), one O(23), one O(5), and one O(6) atom to form PO4 tetrahedra that share  a cornercorner with one Fe(1)O6 octahedra,  a cornercorner with one Fe(2)O6 octahedra, and  a cornercorner with one P(6)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 48-56°. In the fourth P site, P(4) is bonded to one O(16), one O(22), one O(25), and one O(3) atom to form PO4 tetrahedra that share  a cornercorner with one Fe(1)O6 octahedra,  a cornercorner with one Fe(2)O6 octahedra,  a cornercorner with one Fe(4)O6 octahedra, and  a cornercorner with one P(8)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 34-50°. In the fifth P site, P(5) is bonded to one O(10), one O(13), one O(2), and one O(8) atom to form PO4 tetrahedra that share  a cornercorner with one Fe(1)O6 octahedra, corners with two equivalent Fe(2)O6 octahedra, and  a cornercorner with one P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 31-47°. In the sixth P site, P(6) is bonded to one O(12), one O(15), one O(6), and one O(9) atom to form PO4 tetrahedra that share  a cornercorner with one Fe(1)O6 octahedra,  a cornercorner with one Fe(3)O6 octahedra,  a cornercorner with one Fe(4)O6 octahedra, and  a cornercorner with one P(3)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 39-43°. In the seventh P site, P(7) is bonded to one O(24), one O(27), one O(28), and one O(7) atom to form PO4 tetrahedra that share  a cornercorner with one Fe(4)O6 octahedra, corners with two equivalent Fe(3)O6 octahedra, and  a cornercorner with one P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 34-51°. In the eighth P site, P(8) is bonded to one O(14), one O(17), one O(3), and one O(4) atom to form PO4 tetrahedra that share  a cornercorner with one Fe(3)O6 octahedra,  a cornercorner with one Fe(4)O6 octahedra, and  a cornercorner with one P(4)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 46-51°. There are twenty-eight inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Li(3), one Fe(2), and one P(1) atom. In the second O site, O(2) is bonded in a bent 150 degrees geometry to one Fe(2) and one P(5) atom. In the third O site, O(3) is bonded in a bent 120 degrees geometry to one P(4) and one P(8) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Li(2), one Li(3), and one P(8) atom. In the fifth O site, O(5) is bonded in a bent 150 degrees geometry to one Li(3) and one P(3) atom. In the sixth O site, O(6) is bonded in a bent 120 degrees geometry to one P(3) and one P(6) atom. In the seventh O site, O(7) is bonded in a bent 150 degrees geometry to one Fe(3) and one P(7) atom. In the eighth O site, O(8) is bonded in a 3-coordinate geometry to one Li(1), one Fe(1), and one P(5) atom. In the ninth O site, O(9) is bonded in a distorted trigonal planar geometry to one Li(1), one Fe(4), and one P(6) atom. In the tenth O site, O(10) is bonded in a distorted bent 150 degrees geometry to one P(1) and one P(5) atom. In the eleventh O site, O(11) is bonded in a 3-coordinate geometry to one Li(2), one Fe(4), and one P(1) atom. In the twelfth O site, O(12) is bonded in a bent 150 degrees geometry to one Fe(1) and one P(6) atom. In the thirteenth O site, O(13) is bonded in a distorted bent 120 degrees geometry to one Fe(2) and one P(5) atom. In the fourteenth O site, O(14) is bonded in a distorted trigonal planar geometry to one Li(1), one Fe(4), and one P(8) atom. In the fifteenth O site, O(15) is bonded in a 3-coordinate geometry to one Li(4), one Fe(3), and one P(6) atom. In the sixteenth O site, O(16) is bonded in a 3-coordinate geometry to one Li(1), one Fe(1), and one P(4) atom. In the seventeenth O site, O(17) is bonded in a 3-coordinate geometry to one Li(4), one Fe(3), and one P(8) atom. In the eighteenth O site, O(18) is bonded in a distorted bent 120 degrees geometry to one Fe(3) and one P(2) atom. In the nineteenth O site, O(19) is bonded in a 3-coordinate geometry to one Fe(3), one Fe(4), and one P(1) atom. In the twentieth O site, O(20) is bonded in a distorted trigonal planar geometry to one Li(4), one Fe(2), and one P(3) atom. In the twenty-first O site, O(21) is bonded in a 3-coordinate geometry to one Fe(1), one Fe(2), and one P(2) atom. In the twenty-second O site, O(22) is bonded in a 3-coordinate geometry to one Li(4), one Fe(2), and one P(4) atom. In the twenty-third O site, O(23) is bonded in a distorted T-shaped geometry to one Li(1), one Fe(1), and one P(3) atom. In the twenty-fourth O site, O(24) is bonded in a 3-coordinate geometry to one Li(4), one Fe(3), and one P(7) atom. In the twenty-fifth O site, O(25) is bonded in a distorted trigonal planar geometry to one Li(2), one Fe(4), and one P(4) atom. In the twenty-sixth O site, O(26) is bonded in a 3-coordinate geometry to one Li(2), one Fe(1), and one P(2) atom. In the twenty-seventh O site, O(27) is bonded in a bent 120 degrees geometry to one P(2) and one P(7) atom. In the twenty-eighth O site, O(28) is bonded in a 2-coordinate geometry to one Fe(4) and one P(7) atom.
LiFeP2O7 crystallizes in the triclinic P1 space group. There are four inequivalent Li sites. In the first Li site, Li(1) is bonded in a distorted pentagonal planar geometry to one O(14), one O(16), one O(23), one O(8), and one O(9) atom. The Li(1)-O(14) bond length is 2.05 Å. The Li(1)-O(16) bond length is 2.34 Å. The Li(1)-O(23) bond length is 2.02 Å. The Li(1)-O(8) bond length is 2.32 Å. The Li(1)-O(9) bond length is 2.16 Å. In the second Li site, Li(2) is bonded in a 4-coordinate geometry to one O(11), one O(25), one O(26), and one O(4) atom. The Li(2)-O(11) bond length is 2.14 Å. The Li(2)-O(25) bond length is 2.33 Å. The Li(2)-O(26) bond length is 2.14 Å. The Li(2)-O(4) bond length is 2.04 Å. In the third Li site, Li(3) is bonded in a distorted trigonal non-coplanar geometry to one O(1), one O(4), and one O(5) atom. The Li(3)-O(1) bond length is 2.30 Å. The Li(3)-O(4) bond length is 2.00 Å. The Li(3)-O(5) bond length is 1.86 Å. In the fourth Li site, Li(4) is bonded in a 5-coordinate geometry to one O(15), one O(17), one O(20), one O(22), and one O(24) atom. The Li(4)-O(15) bond length is 2.06 Å. The Li(4)-O(17) bond length is 2.39 Å. The Li(4)-O(20) bond length is 2.05 Å. The Li(4)-O(22) bond length is 2.14 Å. The Li(4)-O(24) bond length is 2.13 Å. There are four inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(12), one O(16), one O(21), one O(23), one O(26), and one O(8) atom to form FeO6 octahedra that share  a cornercorner with one Fe(2)O6 octahedra,  a cornercorner with one P(3)O4 tetrahedra,  a cornercorner with one P(4)O4 tetrahedra,  a cornercorner with one P(5)O4 tetrahedra,  a cornercorner with one P(6)O4 tetrahedra, and  an edgeedge with one P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 55°. The Fe(1)-O(12) bond length is 1.94 Å. The Fe(1)-O(16) bond length is 2.01 Å. The Fe(1)-O(21) bond length is 2.27 Å. The Fe(1)-O(23) bond length is 1.97 Å. The Fe(1)-O(26) bond length is 2.14 Å. The Fe(1)-O(8) bond length is 2.05 Å. In the second Fe site, Fe(2) is bonded to one O(1), one O(13), one O(2), one O(20), one O(21), and one O(22) atom to form FeO6 octahedra that share  a cornercorner with one Fe(1)O6 octahedra,  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(2)O4 tetrahedra,  a cornercorner with one P(3)O4 tetrahedra,  a cornercorner with one P(4)O4 tetrahedra, and corners with two equivalent P(5)O4 tetrahedra. The corner-sharing octahedral tilt angles are 55°. The Fe(2)-O(1) bond length is 2.13 Å. The Fe(2)-O(13) bond length is 2.02 Å. The Fe(2)-O(2) bond length is 1.99 Å. The Fe(2)-O(20) bond length is 1.99 Å. The Fe(2)-O(21) bond length is 2.15 Å. The Fe(2)-O(22) bond length is 2.05 Å. In the third Fe site, Fe(3) is bonded to one O(15), one O(17), one O(18), one O(19), one O(24), and one O(7) atom to form FeO6 octahedra that share  a cornercorner with one Fe(4)O6 octahedra,  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(2)O4 tetrahedra,  a cornercorner with one P(6)O4 tetrahedra,  a cornercorner with one P(8)O4 tetrahedra, and corners with two equivalent P(7)O4 tetrahedra. The corner-sharing octahedral tilt angles are 59°. The Fe(3)-O(15) bond length is 2.07 Å. The Fe(3)-O(17) bond length is 1.99 Å. The Fe(3)-O(18) bond length is 1.99 Å. The Fe(3)-O(19) bond length is 2.09 Å. The Fe(3)-O(24) bond length is 2.14 Å. The Fe(3)-O(7) bond length is 1.95 Å. In the fourth Fe site, Fe(4) is bonded to one O(11), one O(14), one O(19), one O(25), one O(28), and one O(9) atom to form FeO6 octahedra that share  a cornercorner with one Fe(3)O6 octahedra,  a cornercorner with one P(4)O4 tetrahedra,  a cornercorner with one P(6)O4 tetrahedra,  a cornercorner with one P(7)O4 tetrahedra,  a cornercorner with one P(8)O4 tetrahedra, and  an edgeedge with one P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 59°. The Fe(4)-O(11) bond length is 2.18 Å. The Fe(4)-O(14) bond length is 1.97 Å. The Fe(4)-O(19) bond length is 2.26 Å. The Fe(4)-O(25) bond length is 1.99 Å. The Fe(4)-O(28) bond length is 2.00 Å. The Fe(4)-O(9) bond length is 1.94 Å. There are eight inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(10), one O(11), and one O(19) atom to form PO4 tetrahedra that share  a cornercorner with one Fe(2)O6 octahedra,  a cornercorner with one Fe(3)O6 octahedra,  a cornercorner with one P(5)O4 tetrahedra, and  an edgeedge with one Fe(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 49-51°. The P(1)-O(1) bond length is 1.53 Å. The P(1)-O(10) bond length is 1.60 Å. The P(1)-O(11) bond length is 1.55 Å. The P(1)-O(19) bond length is 1.56 Å. In the second P site, P(2) is bonded to one O(18), one O(21), one O(26), and one O(27) atom to form PO4 tetrahedra that share  a cornercorner with one Fe(2)O6 octahedra,  a cornercorner with one Fe(3)O6 octahedra,  a cornercorner with one P(7)O4 tetrahedra, and  an edgeedge with one Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 45-50°. The P(2)-O(18) bond length is 1.52 Å. The P(2)-O(21) bond length is 1.55 Å. The P(2)-O(26) bond length is 1.54 Å. The P(2)-O(27) bond length is 1.61 Å. In the third P site, P(3) is bonded to one O(20), one O(23), one O(5), and one O(6) atom to form PO4 tetrahedra that share  a cornercorner with one Fe(1)O6 octahedra,  a cornercorner with one Fe(2)O6 octahedra, and  a cornercorner with one P(6)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 48-56°. The P(3)-O(20) bond length is 1.55 Å. The P(3)-O(23) bond length is 1.55 Å. The P(3)-O(5) bond length is 1.49 Å. The P(3)-O(6) bond length is 1.63 Å. In the fourth P site, P(4) is bonded to one O(16), one O(22), one O(25), and one O(3) atom to form PO4 tetrahedra that share  a cornercorner with one Fe(1)O6 octahedra,  a cornercorner with one Fe(2)O6 octahedra,  a cornercorner with one Fe(4)O6 octahedra, and  a cornercorner with one P(8)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 34-50°. The P(4)-O(16) bond length is 1.53 Å. The P(4)-O(22) bond length is 1.53 Å. The P(4)-O(25) bond length is 1.54 Å. The P(4)-O(3) bond length is 1.61 Å. In the fifth P site, P(5) is bonded to one O(10), one O(13), one O(2), and one O(8) atom to form PO4 tetrahedra that share  a cornercorner with one Fe(1)O6 octahedra, corners with two equivalent Fe(2)O6 octahedra, and  a cornercorner with one P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 31-47°. The P(5)-O(10) bond length is 1.63 Å. The P(5)-O(13) bond length is 1.53 Å. The P(5)-O(2) bond length is 1.53 Å. The P(5)-O(8) bond length is 1.53 Å. In the sixth P site, P(6) is bonded to one O(12), one O(15), one O(6), and one O(9) atom to form PO4 tetrahedra that share  a cornercorner with one Fe(1)O6 octahedra,  a cornercorner with one Fe(3)O6 octahedra,  a cornercorner with one Fe(4)O6 octahedra, and  a cornercorner with one P(3)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 39-43°. The P(6)-O(12) bond length is 1.52 Å. The P(6)-O(15) bond length is 1.52 Å. The P(6)-O(6) bond length is 1.60 Å. The P(6)-O(9) bond length is 1.55 Å. In the seventh P site, P(7) is bonded to one O(24), one O(27), one O(28), and one O(7) atom to form PO4 tetrahedra that share  a cornercorner with one Fe(4)O6 octahedra, corners with two equivalent Fe(3)O6 octahedra, and  a cornercorner with one P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 34-51°. The P(7)-O(24) bond length is 1.53 Å. The P(7)-O(27) bond length is 1.62 Å. The P(7)-O(28) bond length is 1.54 Å. The P(7)-O(7) bond length is 1.53 Å. In the eighth P site, P(8) is bonded to one O(14), one O(17), one O(3), and one O(4) atom to form PO4 tetrahedra that share  a cornercorner with one Fe(3)O6 octahedra,  a cornercorner with one Fe(4)O6 octahedra, and  a cornercorner with one P(4)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 46-51°. The P(8)-O(14) bond length is 1.55 Å. The P(8)-O(17) bond length is 1.53 Å. The P(8)-O(3) bond length is 1.63 Å. The P(8)-O(4) bond length is 1.51 Å. There are twenty-eight inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Li(3), one Fe(2), and one P(1) atom. In the second O site, O(2) is bonded in a bent 150 degrees geometry to one Fe(2) and one P(5) atom. In the third O site, O(3) is bonded in a bent 120 degrees geometry to one P(4) and one P(8) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Li(2), one Li(3), and one P(8) atom. In the fifth O site, O(5) is bonded in a bent 150 degrees geometry to one Li(3) and one P(3) atom. In the sixth O site, O(6) is bonded in a bent 120 degrees geometry to one P(3) and one P(6) atom. In the seventh O site, O(7) is bonded in a bent 150 degrees geometry to one Fe(3) and one P(7) atom. In the eighth O site, O(8) is bonded in a 3-coordinate geometry to one Li(1), one Fe(1), and one P(5) atom. In the ninth O site, O(9) is bonded in a distorted trigonal planar geometry to one Li(1), one Fe(4), and one P(6) atom. In the tenth O site, O(10) is bonded in a distorted bent 150 degrees geometry to one P(1) and one P(5) atom. In the eleventh O site, O(11) is bonded in a 3-coordinate geometry to one Li(2), one Fe(4), and one P(1) atom. In the twelfth O site, O(12) is bonded in a bent 150 degrees geometry to one Fe(1) and one P(6) atom. In the thirteenth O site, O(13) is bonded in a distorted bent 120 degrees geometry to one Fe(2) and one P(5) atom. In the fourteenth O site, O(14) is bonded in a distorted trigonal planar geometry to one Li(1), one Fe(4), and one P(8) atom. In the fifteenth O site, O(15) is bonded in a 3-coordinate geometry to one Li(4), one Fe(3), and one P(6) atom. In the sixteenth O site, O(16) is bonded in a 3-coordinate geometry to one Li(1), one Fe(1), and one P(4) atom. In the seventeenth O site, O(17) is bonded in a 3-coordinate geometry to one Li(4), one Fe(3), and one P(8) atom. In the eighteenth O site, O(18) is bonded in a distorted bent 120 degrees geometry to one Fe(3) and one P(2) atom. In the nineteenth O site, O(19) is bonded in a 3-coordinate geometry to one Fe(3), one Fe(4), and one P(1) atom. In the twentieth O site, O(20) is bonded in a distorted trigonal planar geometry to one Li(4), one Fe(2), and one P(3) atom. In the twenty-first O site, O(21) is bonded in a 3-coordinate geometry to one Fe(1), one Fe(2), and one P(2) atom. In the twenty-second O site, O(22) is bonded in a 3-coordinate geometry to one Li(4), one Fe(2), and one P(4) atom. In the twenty-third O site, O(23) is bonded in a distorted T-shaped geometry to one Li(1), one Fe(1), and one P(3) atom. In the twenty-fourth O site, O(24) is bonded in a 3-coordinate geometry to one Li(4), one Fe(3), and one P(7) atom. In the twenty-fifth O site, O(25) is bonded in a distorted trigonal planar geometry to one Li(2), one Fe(4), and one P(4) atom. In the twenty-sixth O site, O(26) is bonded in a 3-coordinate geometry to one Li(2), one Fe(1), and one P(2) atom. In the twenty-seventh O site, O(27) is bonded in a bent 120 degrees geometry to one P(2) and one P(7) atom. In the twenty-eighth O site, O(28) is bonded in a 2-coordinate geometry to one Fe(4) and one P(7) atom.