The structure described by Mg3Bi2(PO6)2 crystallizes in the monoclinic Pm space group. There are three inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to one O(3), two equivalent O(2), and two equivalent O(6) atoms to form MgO5 square pyramids that share  a cornercorner with one P(1)O4 tetrahedra, corners with two equivalent P(2)O4 tetrahedra, and  an edgeedge with one Mg(2)O5 trigonal bipyramid. In the second Mg site, Mg(2) is bonded to one O(5), two equivalent O(1), and two equivalent O(2) atoms to form distorted MgO5 trigonal bipyramids that share corners with two equivalent Mg(3)O5 square pyramids,  a cornercorner with one P(1)O4 tetrahedra, corners with two equivalent P(2)O4 tetrahedra, and  an edgeedge with one Mg(1)O5 square pyramid. In the third Mg site, Mg(3) is bonded to one O(4), two equivalent O(1), and two equivalent O(7) atoms to form MgO5 square pyramids that share  a cornercorner with one P(2)O4 tetrahedra, corners with two equivalent P(1)O4 tetrahedra, and corners with two equivalent Mg(2)O5 trigonal bipyramids. There are two inequivalent Bi sites. In the first Bi site, Bi(1) is bonded in a 4-coordinate geometry to two equivalent O(1) and two equivalent O(6) atoms. In the second Bi site, Bi(2) is bonded in a 4-coordinate geometry to two equivalent O(1) and two equivalent O(6) atoms. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(3), one O(5), and two equivalent O(7) atoms to form PO4 tetrahedra that share  a cornercorner with one Mg(1)O5 square pyramid, corners with two equivalent Mg(3)O5 square pyramids, and  a cornercorner with one Mg(2)O5 trigonal bipyramid. In the second P site, P(2) is bonded to one O(4), one O(8), and two equivalent O(2) atoms to form PO4 tetrahedra that share  a cornercorner with one Mg(3)O5 square pyramid, corners with two equivalent Mg(1)O5 square pyramids, and corners with two equivalent Mg(2)O5 trigonal bipyramids. There are eight inequivalent O sites. In the first O site, O(1) is bonded to one Mg(2), one Mg(3), one Bi(1), and one Bi(2) atom to form edge-sharing OMg2Bi2 tetrahedra. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Mg(1), one Mg(2), and one P(2) atom. In the third O site, O(3) is bonded in a linear geometry to one Mg(1) and one P(1) atom. In the fourth O site, O(4) is bonded in a bent 150 degrees geometry to one Mg(3) and one P(2) atom. In the fifth O site, O(5) is bonded in a bent 150 degrees geometry to one Mg(2) and one P(1) atom. In the sixth O site, O(6) is bonded in a trigonal non-coplanar geometry to one Mg(1), one Bi(1), and one Bi(2) atom. In the seventh O site, O(7) is bonded in a distorted bent 150 degrees geometry to one Mg(3) and one P(1) atom. In the eighth O site, O(8) is bonded in a single-bond geometry to one P(2) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Mg3Bi2(PO6)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.355
_cell_length_b   7.157
_cell_length_c   7.384
_cell_angle_alpha   65.639
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   257.816
_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
  Mg  Mg0  1  0.000  0.722  0.094  1.0
  Mg  Mg1  1  0.000  0.101  0.702  1.0
  Mg  Mg2  1  0.500  0.275  0.912  1.0
  Bi  Bi3  1  0.500  0.398  0.412  1.0
  Bi  Bi4  1  0.000  0.606  0.589  1.0
  P  P5  1  0.000  0.204  0.194  1.0
  P  P6  1  0.500  0.800  0.806  1.0
  O  O7  1  0.251  0.328  0.676  1.0
  O  O8  1  0.742  0.877  0.875  1.0
  O  O9  1  0.000  0.440  0.113  1.0
  O  O10  1  0.500  0.564  0.897  1.0
  O  O11  1  0.749  0.328  0.676  1.0
  O  O12  1  0.000  0.109  0.424  1.0
  O  O13  1  0.238  0.656  0.329  1.0
  O  O14  1  0.762  0.656  0.329  1.0
  O  O15  1  0.231  0.133  0.113  1.0
  O  O16  1  0.500  0.892  0.578  1.0
  O  O17  1  0.258  0.877  0.875  1.0
  O  O18  1  0.769  0.133  0.113  1.0
[/CIF]
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The structure described by Mg3Bi2(PO6)2 crystallizes in the monoclinic Pm space group. There are three inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to one O(3), two equivalent O(2), and two equivalent O(6) atoms to form MgO5 square pyramids that share  a cornercorner with one P(1)O4 tetrahedra, corners with two equivalent P(2)O4 tetrahedra, and  an edgeedge with one Mg(2)O5 trigonal bipyramid. In the second Mg site, Mg(2) is bonded to one O(5), two equivalent O(1), and two equivalent O(2) atoms to form distorted MgO5 trigonal bipyramids that share corners with two equivalent Mg(3)O5 square pyramids,  a cornercorner with one P(1)O4 tetrahedra, corners with two equivalent P(2)O4 tetrahedra, and  an edgeedge with one Mg(1)O5 square pyramid. In the third Mg site, Mg(3) is bonded to one O(4), two equivalent O(1), and two equivalent O(7) atoms to form MgO5 square pyramids that share  a cornercorner with one P(2)O4 tetrahedra, corners with two equivalent P(1)O4 tetrahedra, and corners with two equivalent Mg(2)O5 trigonal bipyramids. There are two inequivalent Bi sites. In the first Bi site, Bi(1) is bonded in a 4-coordinate geometry to two equivalent O(1) and two equivalent O(6) atoms. In the second Bi site, Bi(2) is bonded in a 4-coordinate geometry to two equivalent O(1) and two equivalent O(6) atoms. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(3), one O(5), and two equivalent O(7) atoms to form PO4 tetrahedra that share  a cornercorner with one Mg(1)O5 square pyramid, corners with two equivalent Mg(3)O5 square pyramids, and  a cornercorner with one Mg(2)O5 trigonal bipyramid. In the second P site, P(2) is bonded to one O(4), one O(8), and two equivalent O(2) atoms to form PO4 tetrahedra that share  a cornercorner with one Mg(3)O5 square pyramid, corners with two equivalent Mg(1)O5 square pyramids, and corners with two equivalent Mg(2)O5 trigonal bipyramids. There are eight inequivalent O sites. In the first O site, O(1) is bonded to one Mg(2), one Mg(3), one Bi(1), and one Bi(2) atom to form edge-sharing OMg2Bi2 tetrahedra. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Mg(1), one Mg(2), and one P(2) atom. In the third O site, O(3) is bonded in a linear geometry to one Mg(1) and one P(1) atom. In the fourth O site, O(4) is bonded in a bent 150 degrees geometry to one Mg(3) and one P(2) atom. In the fifth O site, O(5) is bonded in a bent 150 degrees geometry to one Mg(2) and one P(1) atom. In the sixth O site, O(6) is bonded in a trigonal non-coplanar geometry to one Mg(1), one Bi(1), and one Bi(2) atom. In the seventh O site, O(7) is bonded in a distorted bent 150 degrees geometry to one Mg(3) and one P(1) atom. In the eighth O site, O(8) is bonded in a single-bond geometry to one P(2) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Mg3Bi2(PO6)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.355
_cell_length_b   7.157
_cell_length_c   7.384
_cell_angle_alpha   65.639
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   257.816
_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
  Mg  Mg0  1  0.000  0.722  0.094  1.0
  Mg  Mg1  1  0.000  0.101  0.702  1.0
  Mg  Mg2  1  0.500  0.275  0.912  1.0
  Bi  Bi3  1  0.500  0.398  0.412  1.0
  Bi  Bi4  1  0.000  0.606  0.589  1.0
  P  P5  1  0.000  0.204  0.194  1.0
  P  P6  1  0.500  0.800  0.806  1.0
  O  O7  1  0.251  0.328  0.676  1.0
  O  O8  1  0.742  0.877  0.875  1.0
  O  O9  1  0.000  0.440  0.113  1.0
  O  O10  1  0.500  0.564  0.897  1.0
  O  O11  1  0.749  0.328  0.676  1.0
  O  O12  1  0.000  0.109  0.424  1.0
  O  O13  1  0.238  0.656  0.329  1.0
  O  O14  1  0.762  0.656  0.329  1.0
  O  O15  1  0.231  0.133  0.113  1.0
  O  O16  1  0.500  0.892  0.578  1.0
  O  O17  1  0.258  0.877  0.875  1.0
  O  O18  1  0.769  0.133  0.113  1.0
[/CIF]
.