BaFeBP2O9 crystallizes in the triclinic P-1 space group. Ba(1) is bonded in a 10-coordinate geometry to one O(4), one O(5), one O(6), one O(8), two equivalent O(1), two equivalent O(2), and two equivalent O(7) atoms. Fe(1) is bonded to one O(1), one O(2), one O(5), one O(6), one O(7), and one O(9) atom to form distorted FeO6 octahedra that share  a cornercorner with one B(1)O4 tetrahedra, corners with two equivalent P(1)O4 tetrahedra, and corners with three equivalent P(2)O4 tetrahedra. B(1) is bonded to one O(3), one O(4), one O(8), and one O(9) atom to form BO4 tetrahedra that share  a cornercorner with one Fe(1)O6 octahedra,  a cornercorner with one P(2)O4 tetrahedra, and corners with two equivalent P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 42°. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form PO4 tetrahedra that share corners with two equivalent Fe(1)O6 octahedra and corners with two equivalent B(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 43-60°. In the second P site, P(2) is bonded to one O(5), one O(6), one O(7), and one O(8) atom to form PO4 tetrahedra that share corners with three equivalent Fe(1)O6 octahedra and  a cornercorner with one B(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 41-48°. There are nine inequivalent O sites. In the first O site, O(1) is bonded in a 2-coordinate geometry to two equivalent Ba(1), one Fe(1), and one P(1) atom. In the second O site, O(2) is bonded in a 1-coordinate geometry to two equivalent Ba(1), one Fe(1), and one P(1) atom. In the third O site, O(3) is bonded in a bent 120 degrees geometry to one B(1) and one P(1) atom. In the fourth O site, O(4) is bonded in a 2-coordinate geometry to one Ba(1), one B(1), and one P(1) atom. In the fifth O site, O(5) is bonded in a 2-coordinate geometry to one Ba(1), one Fe(1), and one P(2) atom. In the sixth O site, O(6) is bonded in a 3-coordinate geometry to one Ba(1), one Fe(1), and one P(2) atom. In the seventh O site, O(7) is bonded in a 2-coordinate geometry to two equivalent Ba(1), one Fe(1), and one P(2) atom. In the eighth O site, O(8) is bonded in a distorted bent 120 degrees geometry to one Ba(1), one B(1), and one P(2) atom. In the ninth O site, O(9) is bonded in a distorted bent 150 degrees geometry to one Fe(1) and one B(1) atom.
BaFeBP2O9 crystallizes in the triclinic P-1 space group. Ba(1) is bonded in a 10-coordinate geometry to one O(4), one O(5), one O(6), one O(8), two equivalent O(1), two equivalent O(2), and two equivalent O(7) atoms. The Ba(1)-O(4) bond length is 2.83 Å. The Ba(1)-O(5) bond length is 2.92 Å. The Ba(1)-O(6) bond length is 2.83 Å. The Ba(1)-O(8) bond length is 2.95 Å. There is one shorter (2.97 Å) and one longer (3.01 Å) Ba(1)-O(1) bond length. There is one shorter (2.82 Å) and one longer (2.98 Å) Ba(1)-O(2) bond length. There is one shorter (2.89 Å) and one longer (2.95 Å) Ba(1)-O(7) bond length. Fe(1) is bonded to one O(1), one O(2), one O(5), one O(6), one O(7), and one O(9) atom to form distorted FeO6 octahedra that share  a cornercorner with one B(1)O4 tetrahedra, corners with two equivalent P(1)O4 tetrahedra, and corners with three equivalent P(2)O4 tetrahedra. The Fe(1)-O(1) bond length is 2.11 Å. The Fe(1)-O(2) bond length is 2.27 Å. The Fe(1)-O(5) bond length is 2.10 Å. The Fe(1)-O(6) bond length is 2.05 Å. The Fe(1)-O(7) bond length is 2.08 Å. The Fe(1)-O(9) bond length is 1.83 Å. B(1) is bonded to one O(3), one O(4), one O(8), and one O(9) atom to form BO4 tetrahedra that share  a cornercorner with one Fe(1)O6 octahedra,  a cornercorner with one P(2)O4 tetrahedra, and corners with two equivalent P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 42°. The B(1)-O(3) bond length is 1.51 Å. The B(1)-O(4) bond length is 1.56 Å. The B(1)-O(8) bond length is 1.50 Å. The B(1)-O(9) bond length is 1.38 Å. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form PO4 tetrahedra that share corners with two equivalent Fe(1)O6 octahedra and corners with two equivalent B(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 43-60°. The P(1)-O(1) bond length is 1.55 Å. The P(1)-O(2) bond length is 1.55 Å. The P(1)-O(3) bond length is 1.56 Å. The P(1)-O(4) bond length is 1.57 Å. In the second P site, P(2) is bonded to one O(5), one O(6), one O(7), and one O(8) atom to form PO4 tetrahedra that share corners with three equivalent Fe(1)O6 octahedra and  a cornercorner with one B(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 41-48°. The P(2)-O(5) bond length is 1.53 Å. The P(2)-O(6) bond length is 1.54 Å. The P(2)-O(7) bond length is 1.57 Å. The P(2)-O(8) bond length is 1.58 Å. There are nine inequivalent O sites. In the first O site, O(1) is bonded in a 2-coordinate geometry to two equivalent Ba(1), one Fe(1), and one P(1) atom. In the second O site, O(2) is bonded in a 1-coordinate geometry to two equivalent Ba(1), one Fe(1), and one P(1) atom. In the third O site, O(3) is bonded in a bent 120 degrees geometry to one B(1) and one P(1) atom. In the fourth O site, O(4) is bonded in a 2-coordinate geometry to one Ba(1), one B(1), and one P(1) atom. In the fifth O site, O(5) is bonded in a 2-coordinate geometry to one Ba(1), one Fe(1), and one P(2) atom. In the sixth O site, O(6) is bonded in a 3-coordinate geometry to one Ba(1), one Fe(1), and one P(2) atom. In the seventh O site, O(7) is bonded in a 2-coordinate geometry to two equivalent Ba(1), one Fe(1), and one P(2) atom. In the eighth O site, O(8) is bonded in a distorted bent 120 degrees geometry to one Ba(1), one B(1), and one P(2) atom. In the ninth O site, O(9) is bonded in a distorted bent 150 degrees geometry to one Fe(1) and one B(1) atom.