The material structure described by Cr9(PO4)8 crystallizes in the triclinic P-1 space group. There are six inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to one O(10), one O(11), one O(2), one O(5), one O(8), and one O(9) atom to form distorted CrO6 octahedra that share  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(4)O4 tetrahedra, corners with two equivalent P(2)O4 tetrahedra,  an edgeedge with one Cr(6)O6 octahedra, and  an edgeedge with one P(3)O4 tetrahedra. In the second Cr site, Cr(2) is bonded to one O(13), one O(15), one O(16), one O(3), one O(4), and one O(6) atom to form CrO6 octahedra that share  a cornercorner with one Cr(6)O6 octahedra,  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(3)O4 tetrahedra, corners with two equivalent P(4)O4 tetrahedra, corners with two equivalent Cr(4)O5 trigonal bipyramids, and  an edgeedge with one P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 40°. In the third Cr site, Cr(3) is bonded in a square co-planar geometry to two equivalent O(1) and two equivalent O(11) atoms. In the fourth Cr site, Cr(4) is bonded to one O(1), one O(12), one O(14), one O(15), and one O(16) atom to form CrO5 trigonal bipyramids that share corners with two equivalent Cr(2)O6 octahedra,  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(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 61-62°. In the fifth Cr site, Cr(5) is bonded in a square co-planar geometry to two equivalent O(7) and two equivalent O(8) atoms. In the sixth Cr site, Cr(6) is bonded to two equivalent O(2), two equivalent O(5), and two equivalent O(6) atoms to form CrO6 octahedra that share corners with two equivalent Cr(2)O6 octahedra, corners with two equivalent P(2)O4 tetrahedra, edges with two equivalent Cr(1)O6 octahedra, and edges with two equivalent P(3)O4 tetrahedra. The corner-sharing octahedral tilt angles are 40°. There are four inequivalent P sites. In the first P site, P(1) is bonded to one O(15), one O(16), one O(4), and one O(9) atom to form PO4 tetrahedra that share  a cornercorner with one Cr(1)O6 octahedra,  a cornercorner with one Cr(2)O6 octahedra, corners with two equivalent Cr(4)O5 trigonal bipyramids, and  an edgeedge with one Cr(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 44-55°. In the second P site, P(2) is bonded to one O(10), one O(12), one O(2), and one O(7) atom to form PO4 tetrahedra that share  a cornercorner with one Cr(6)O6 octahedra, corners with two equivalent Cr(1)O6 octahedra, and  a cornercorner with one Cr(4)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 46-57°. In the third P site, P(3) is bonded to one O(11), one O(14), one O(5), and one O(6) atom to form PO4 tetrahedra that share  a cornercorner with one Cr(2)O6 octahedra,  a cornercorner with one Cr(4)O5 trigonal bipyramid,  an edgeedge with one Cr(1)O6 octahedra, and  an edgeedge with one Cr(6)O6 octahedra. The corner-sharing octahedral tilt angles are 55°. In the fourth P site, P(4) is bonded to one O(1), one O(13), one O(3), and one O(8) atom to form PO4 tetrahedra that share  a cornercorner with one Cr(1)O6 octahedra, corners with two equivalent Cr(2)O6 octahedra, and  a cornercorner with one Cr(4)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 37-48°. There are sixteen inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Cr(3), one Cr(4), and one P(4) atom. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Cr(1), one Cr(6), and one P(2) atom. In the third O site, O(3) is bonded in a distorted bent 120 degrees geometry to one Cr(2) and one P(4) atom. In the fourth O site, O(4) is bonded in a distorted bent 150 degrees geometry to one Cr(2) and one P(1) atom. In the fifth O site, O(5) is bonded in a distorted trigonal non-coplanar geometry to one Cr(1), one Cr(6), and one P(3) atom. In the sixth O site, O(6) is bonded in a 3-coordinate geometry to one Cr(2), one Cr(6), and one P(3) atom. In the seventh O site, O(7) is bonded in a bent 120 degrees geometry to one Cr(5) and one P(2) atom. In the eighth O site, O(8) is bonded in a distorted trigonal planar geometry to one Cr(1), one Cr(5), and one P(4) atom. In the ninth O site, O(9) is bonded in a distorted bent 120 degrees geometry to one Cr(1) and one P(1) atom. In the tenth O site, O(10) is bonded in a bent 120 degrees geometry to one Cr(1) and one P(2) atom. In the eleventh O site, O(11) is bonded in a distorted trigonal planar geometry to one Cr(1), one Cr(3), and one P(3) atom. In the twelfth O site, O(12) is bonded in a bent 150 degrees geometry to one Cr(4) and one P(2) atom. In the thirteenth O site, O(13) is bonded in a bent 150 degrees geometry to one Cr(2) and one P(4) atom. In the fourteenth O site, O(14) is bonded in a distorted bent 120 degrees geometry to one Cr(4) and one P(3) atom. In the fifteenth O site, O(15) is bonded in a distorted trigonal planar geometry to one Cr(2), one Cr(4), and one P(1) atom. In the sixteenth O site, O(16) is bonded in a distorted trigonal planar geometry to one Cr(2), one Cr(4), and one P(1) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Cr9(PO4)8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.180
_cell_length_b   8.652
_cell_length_c   8.827
_cell_angle_alpha   100.134
_cell_angle_beta   103.253
_cell_angle_gamma   110.017
_symmetry_Int_Tables_number   1
_cell_volume   615.882
_cell_formula_units_Z   1
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
loop_
 _atom_site_type_symbol
 _atom_site_label
 _atom_site_symmetry_multiplicity
 _atom_site_fract_x
 _atom_site_fract_y
 _atom_site_fract_z
 _atom_site_occupancy
  Cr  Cr0  1  0.943  0.694  0.202  1.0
  Cr  Cr1  1  0.563  0.123  0.290  1.0
  Cr  Cr2  1  0.500  0.500  0.000  1.0
  Cr  Cr3  1  0.532  0.296  0.672  1.0
  Cr  Cr4  1  0.468  0.704  0.328  1.0
  Cr  Cr5  1  0.437  0.877  0.710  1.0
  Cr  Cr6  1  0.000  0.000  0.000  1.0
  Cr  Cr7  1  0.057  0.306  0.798  1.0
  Cr  Cr8  1  0.000  0.500  0.500  1.0
  P  P9  1  0.297  0.964  0.381  1.0
  P  P10  1  0.097  0.386  0.163  1.0
  P  P11  1  0.279  0.474  0.665  1.0
  P  P12  1  0.339  0.126  0.936  1.0
  P  P13  1  0.661  0.874  0.064  1.0
  P  P14  1  0.721  0.526  0.335  1.0
  P  P15  1  0.903  0.614  0.837  1.0
  P  P16  1  0.703  0.036  0.619  1.0
  O  O17  1  0.444  0.266  0.868  1.0
  O  O18  1  0.970  0.506  0.725  1.0
  O  O19  1  0.675  0.051  0.149  1.0
  O  O20  1  0.714  0.099  0.470  1.0
  O  O21  1  0.900  0.668  0.426  1.0
  O  O22  1  0.740  0.366  0.381  1.0
  O  O23  1  0.928  0.790  0.808  1.0
  O  O24  1  0.832  0.860  0.097  1.0
  O  O25  1  0.874  0.077  0.725  1.0
  O  O26  1  0.126  0.923  0.275  1.0
  O  O27  1  0.006  0.653  0.017  1.0
  O  O28  1  0.030  0.494  0.275  1.0
  O  O29  1  0.325  0.949  0.851  1.0
  O  O30  1  0.286  0.901  0.530  1.0
  O  O31  1  0.100  0.332  0.574  1.0
  O  O32  1  0.260  0.634  0.619  1.0
  O  O33  1  0.072  0.210  0.192  1.0
  O  O34  1  0.168  0.140  0.903  1.0
  O  O35  1  0.290  0.485  0.848  1.0
  O  O36  1  0.710  0.515  0.152  1.0
  O  O37  1  0.277  0.500  0.190  1.0
  O  O38  1  0.582  0.827  0.879  1.0
  O  O39  1  0.417  0.443  0.621  1.0
  O  O40  1  0.583  0.841  0.567  1.0
  O  O41  1  0.391  0.887  0.279  1.0
  O  O42  1  0.556  0.734  0.132  1.0
  O  O43  1  0.417  0.159  0.433  1.0
  O  O44  1  0.583  0.557  0.379  1.0
  O  O45  1  0.418  0.173  0.121  1.0
  O  O46  1  0.723  0.500  0.810  1.0
  O  O47  1  0.609  0.113  0.721  1.0
  O  O48  1  0.994  0.347  0.983  1.0
[/CIF]
.
The material structure described by Cr9(PO4)8 crystallizes in the triclinic P-1 space group. There are six inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to one O(10), one O(11), one O(2), one O(5), one O(8), and one O(9) atom to form distorted CrO6 octahedra that share  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(4)O4 tetrahedra, corners with two equivalent P(2)O4 tetrahedra,  an edgeedge with one Cr(6)O6 octahedra, and  an edgeedge with one P(3)O4 tetrahedra. In the second Cr site, Cr(2) is bonded to one O(13), one O(15), one O(16), one O(3), one O(4), and one O(6) atom to form CrO6 octahedra that share  a cornercorner with one Cr(6)O6 octahedra,  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(3)O4 tetrahedra, corners with two equivalent P(4)O4 tetrahedra, corners with two equivalent Cr(4)O5 trigonal bipyramids, and  an edgeedge with one P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 40°. In the third Cr site, Cr(3) is bonded in a square co-planar geometry to two equivalent O(1) and two equivalent O(11) atoms. In the fourth Cr site, Cr(4) is bonded to one O(1), one O(12), one O(14), one O(15), and one O(16) atom to form CrO5 trigonal bipyramids that share corners with two equivalent Cr(2)O6 octahedra,  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(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 61-62°. In the fifth Cr site, Cr(5) is bonded in a square co-planar geometry to two equivalent O(7) and two equivalent O(8) atoms. In the sixth Cr site, Cr(6) is bonded to two equivalent O(2), two equivalent O(5), and two equivalent O(6) atoms to form CrO6 octahedra that share corners with two equivalent Cr(2)O6 octahedra, corners with two equivalent P(2)O4 tetrahedra, edges with two equivalent Cr(1)O6 octahedra, and edges with two equivalent P(3)O4 tetrahedra. The corner-sharing octahedral tilt angles are 40°. There are four inequivalent P sites. In the first P site, P(1) is bonded to one O(15), one O(16), one O(4), and one O(9) atom to form PO4 tetrahedra that share  a cornercorner with one Cr(1)O6 octahedra,  a cornercorner with one Cr(2)O6 octahedra, corners with two equivalent Cr(4)O5 trigonal bipyramids, and  an edgeedge with one Cr(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 44-55°. In the second P site, P(2) is bonded to one O(10), one O(12), one O(2), and one O(7) atom to form PO4 tetrahedra that share  a cornercorner with one Cr(6)O6 octahedra, corners with two equivalent Cr(1)O6 octahedra, and  a cornercorner with one Cr(4)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 46-57°. In the third P site, P(3) is bonded to one O(11), one O(14), one O(5), and one O(6) atom to form PO4 tetrahedra that share  a cornercorner with one Cr(2)O6 octahedra,  a cornercorner with one Cr(4)O5 trigonal bipyramid,  an edgeedge with one Cr(1)O6 octahedra, and  an edgeedge with one Cr(6)O6 octahedra. The corner-sharing octahedral tilt angles are 55°. In the fourth P site, P(4) is bonded to one O(1), one O(13), one O(3), and one O(8) atom to form PO4 tetrahedra that share  a cornercorner with one Cr(1)O6 octahedra, corners with two equivalent Cr(2)O6 octahedra, and  a cornercorner with one Cr(4)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 37-48°. There are sixteen inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Cr(3), one Cr(4), and one P(4) atom. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Cr(1), one Cr(6), and one P(2) atom. In the third O site, O(3) is bonded in a distorted bent 120 degrees geometry to one Cr(2) and one P(4) atom. In the fourth O site, O(4) is bonded in a distorted bent 150 degrees geometry to one Cr(2) and one P(1) atom. In the fifth O site, O(5) is bonded in a distorted trigonal non-coplanar geometry to one Cr(1), one Cr(6), and one P(3) atom. In the sixth O site, O(6) is bonded in a 3-coordinate geometry to one Cr(2), one Cr(6), and one P(3) atom. In the seventh O site, O(7) is bonded in a bent 120 degrees geometry to one Cr(5) and one P(2) atom. In the eighth O site, O(8) is bonded in a distorted trigonal planar geometry to one Cr(1), one Cr(5), and one P(4) atom. In the ninth O site, O(9) is bonded in a distorted bent 120 degrees geometry to one Cr(1) and one P(1) atom. In the tenth O site, O(10) is bonded in a bent 120 degrees geometry to one Cr(1) and one P(2) atom. In the eleventh O site, O(11) is bonded in a distorted trigonal planar geometry to one Cr(1), one Cr(3), and one P(3) atom. In the twelfth O site, O(12) is bonded in a bent 150 degrees geometry to one Cr(4) and one P(2) atom. In the thirteenth O site, O(13) is bonded in a bent 150 degrees geometry to one Cr(2) and one P(4) atom. In the fourteenth O site, O(14) is bonded in a distorted bent 120 degrees geometry to one Cr(4) and one P(3) atom. In the fifteenth O site, O(15) is bonded in a distorted trigonal planar geometry to one Cr(2), one Cr(4), and one P(1) atom. In the sixteenth O site, O(16) is bonded in a distorted trigonal planar geometry to one Cr(2), one Cr(4), and one P(1) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Cr9(PO4)8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.180
_cell_length_b   8.652
_cell_length_c   8.827
_cell_angle_alpha   100.134
_cell_angle_beta   103.253
_cell_angle_gamma   110.017
_symmetry_Int_Tables_number   1
_cell_volume   615.882
_cell_formula_units_Z   1
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
loop_
 _atom_site_type_symbol
 _atom_site_label
 _atom_site_symmetry_multiplicity
 _atom_site_fract_x
 _atom_site_fract_y
 _atom_site_fract_z
 _atom_site_occupancy
  Cr  Cr0  1  0.943  0.694  0.202  1.0
  Cr  Cr1  1  0.563  0.123  0.290  1.0
  Cr  Cr2  1  0.500  0.500  0.000  1.0
  Cr  Cr3  1  0.532  0.296  0.672  1.0
  Cr  Cr4  1  0.468  0.704  0.328  1.0
  Cr  Cr5  1  0.437  0.877  0.710  1.0
  Cr  Cr6  1  0.000  0.000  0.000  1.0
  Cr  Cr7  1  0.057  0.306  0.798  1.0
  Cr  Cr8  1  0.000  0.500  0.500  1.0
  P  P9  1  0.297  0.964  0.381  1.0
  P  P10  1  0.097  0.386  0.163  1.0
  P  P11  1  0.279  0.474  0.665  1.0
  P  P12  1  0.339  0.126  0.936  1.0
  P  P13  1  0.661  0.874  0.064  1.0
  P  P14  1  0.721  0.526  0.335  1.0
  P  P15  1  0.903  0.614  0.837  1.0
  P  P16  1  0.703  0.036  0.619  1.0
  O  O17  1  0.444  0.266  0.868  1.0
  O  O18  1  0.970  0.506  0.725  1.0
  O  O19  1  0.675  0.051  0.149  1.0
  O  O20  1  0.714  0.099  0.470  1.0
  O  O21  1  0.900  0.668  0.426  1.0
  O  O22  1  0.740  0.366  0.381  1.0
  O  O23  1  0.928  0.790  0.808  1.0
  O  O24  1  0.832  0.860  0.097  1.0
  O  O25  1  0.874  0.077  0.725  1.0
  O  O26  1  0.126  0.923  0.275  1.0
  O  O27  1  0.006  0.653  0.017  1.0
  O  O28  1  0.030  0.494  0.275  1.0
  O  O29  1  0.325  0.949  0.851  1.0
  O  O30  1  0.286  0.901  0.530  1.0
  O  O31  1  0.100  0.332  0.574  1.0
  O  O32  1  0.260  0.634  0.619  1.0
  O  O33  1  0.072  0.210  0.192  1.0
  O  O34  1  0.168  0.140  0.903  1.0
  O  O35  1  0.290  0.485  0.848  1.0
  O  O36  1  0.710  0.515  0.152  1.0
  O  O37  1  0.277  0.500  0.190  1.0
  O  O38  1  0.582  0.827  0.879  1.0
  O  O39  1  0.417  0.443  0.621  1.0
  O  O40  1  0.583  0.841  0.567  1.0
  O  O41  1  0.391  0.887  0.279  1.0
  O  O42  1  0.556  0.734  0.132  1.0
  O  O43  1  0.417  0.159  0.433  1.0
  O  O44  1  0.583  0.557  0.379  1.0
  O  O45  1  0.418  0.173  0.121  1.0
  O  O46  1  0.723  0.500  0.810  1.0
  O  O47  1  0.609  0.113  0.721  1.0
  O  O48  1  0.994  0.347  0.983  1.0
[/CIF]
.