The crystal structure described by Mg2(PO4)OH crystallizes in the orthorhombic Pnma space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to one O(1), one O(2), one O(4), and two equivalent O(3) atoms to form distorted MgO5 trigonal bipyramids that share corners with two equivalent Mg(2)O6 octahedra, corners with four equivalent P(1)O4 tetrahedra, and edges with two equivalent Mg(2)O6 octahedra. The corner-sharing octahedral tilt angles are 50°. In the second Mg site, Mg(2) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(4) atoms to form MgO6 octahedra that share corners with four equivalent P(1)O4 tetrahedra, corners with two equivalent Mg(1)O5 trigonal bipyramids, edges with two equivalent Mg(2)O6 octahedra, and edges with two equivalent Mg(1)O5 trigonal bipyramids. P(1) is bonded to one O(2), one O(4), and two equivalent O(3) atoms to form PO4 tetrahedra that share corners with four equivalent Mg(2)O6 octahedra and corners with four equivalent Mg(1)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 47-57°. H(1) is bonded in a single-bond geometry to one O(1) atom. There are four inequivalent O sites. In the first O site, O(4) is bonded in a distorted rectangular see-saw-like geometry to one Mg(1), two equivalent Mg(2), and one P(1) atom. In the second O site, O(1) is bonded in a distorted single-bond geometry to one Mg(1), two equivalent Mg(2), and one H(1) atom. In the third O site, O(2) is bonded in a linear geometry to one Mg(1) and one P(1) atom. In the fourth O site, O(3) is bonded in a distorted trigonal planar geometry to one Mg(1), one Mg(2), and one P(1) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Mg2PHO5
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.138
_cell_length_b   7.371
_cell_length_c   8.218
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   371.853
_cell_formula_units_Z   4
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  0.250  0.578  0.178  1.0
  Mg  Mg1  1  0.750  0.422  0.822  1.0
  Mg  Mg2  1  0.750  0.078  0.322  1.0
  Mg  Mg3  1  0.250  0.922  0.678  1.0
  Mg  Mg4  1  0.500  0.000  0.000  1.0
  Mg  Mg5  1  0.000  0.000  0.000  1.0
  Mg  Mg6  1  0.500  0.500  0.500  1.0
  Mg  Mg7  1  0.000  0.500  0.500  1.0
  P  P8  1  0.250  0.334  0.824  1.0
  P  P9  1  0.750  0.666  0.176  1.0
  P  P10  1  0.750  0.834  0.676  1.0
  P  P11  1  0.250  0.166  0.324  1.0
  H  H12  1  0.250  0.732  0.948  1.0
  H  H13  1  0.750  0.268  0.052  1.0
  H  H14  1  0.750  0.232  0.552  1.0
  H  H15  1  0.250  0.768  0.448  1.0
  O  O16  1  0.250  0.814  0.041  1.0
  O  O17  1  0.750  0.186  0.959  1.0
  O  O18  1  0.750  0.314  0.459  1.0
  O  O19  1  0.250  0.686  0.541  1.0
  O  O20  1  0.250  0.440  0.980  1.0
  O  O21  1  0.750  0.560  0.020  1.0
  O  O22  1  0.750  0.940  0.520  1.0
  O  O23  1  0.250  0.060  0.480  1.0
  O  O24  1  0.454  0.125  0.222  1.0
  O  O25  1  0.954  0.875  0.778  1.0
  O  O26  1  0.546  0.625  0.278  1.0
  O  O27  1  0.046  0.375  0.722  1.0
  O  O28  1  0.546  0.875  0.778  1.0
  O  O29  1  0.046  0.125  0.222  1.0
  O  O30  1  0.454  0.375  0.722  1.0
  O  O31  1  0.954  0.625  0.278  1.0
  O  O32  1  0.250  0.373  0.365  1.0
  O  O33  1  0.750  0.627  0.635  1.0
  O  O34  1  0.750  0.873  0.135  1.0
  O  O35  1  0.250  0.127  0.865  1.0
[/CIF]
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The crystal structure described by Mg2(PO4)OH crystallizes in the orthorhombic Pnma space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to one O(1), one O(2), one O(4), and two equivalent O(3) atoms to form distorted MgO5 trigonal bipyramids that share corners with two equivalent Mg(2)O6 octahedra, corners with four equivalent P(1)O4 tetrahedra, and edges with two equivalent Mg(2)O6 octahedra. The corner-sharing octahedral tilt angles are 50°. In the second Mg site, Mg(2) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(4) atoms to form MgO6 octahedra that share corners with four equivalent P(1)O4 tetrahedra, corners with two equivalent Mg(1)O5 trigonal bipyramids, edges with two equivalent Mg(2)O6 octahedra, and edges with two equivalent Mg(1)O5 trigonal bipyramids. P(1) is bonded to one O(2), one O(4), and two equivalent O(3) atoms to form PO4 tetrahedra that share corners with four equivalent Mg(2)O6 octahedra and corners with four equivalent Mg(1)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 47-57°. H(1) is bonded in a single-bond geometry to one O(1) atom. There are four inequivalent O sites. In the first O site, O(4) is bonded in a distorted rectangular see-saw-like geometry to one Mg(1), two equivalent Mg(2), and one P(1) atom. In the second O site, O(1) is bonded in a distorted single-bond geometry to one Mg(1), two equivalent Mg(2), and one H(1) atom. In the third O site, O(2) is bonded in a linear geometry to one Mg(1) and one P(1) atom. In the fourth O site, O(3) is bonded in a distorted trigonal planar geometry to one Mg(1), one Mg(2), and one P(1) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Mg2PHO5
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.138
_cell_length_b   7.371
_cell_length_c   8.218
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   371.853
_cell_formula_units_Z   4
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  0.250  0.578  0.178  1.0
  Mg  Mg1  1  0.750  0.422  0.822  1.0
  Mg  Mg2  1  0.750  0.078  0.322  1.0
  Mg  Mg3  1  0.250  0.922  0.678  1.0
  Mg  Mg4  1  0.500  0.000  0.000  1.0
  Mg  Mg5  1  0.000  0.000  0.000  1.0
  Mg  Mg6  1  0.500  0.500  0.500  1.0
  Mg  Mg7  1  0.000  0.500  0.500  1.0
  P  P8  1  0.250  0.334  0.824  1.0
  P  P9  1  0.750  0.666  0.176  1.0
  P  P10  1  0.750  0.834  0.676  1.0
  P  P11  1  0.250  0.166  0.324  1.0
  H  H12  1  0.250  0.732  0.948  1.0
  H  H13  1  0.750  0.268  0.052  1.0
  H  H14  1  0.750  0.232  0.552  1.0
  H  H15  1  0.250  0.768  0.448  1.0
  O  O16  1  0.250  0.814  0.041  1.0
  O  O17  1  0.750  0.186  0.959  1.0
  O  O18  1  0.750  0.314  0.459  1.0
  O  O19  1  0.250  0.686  0.541  1.0
  O  O20  1  0.250  0.440  0.980  1.0
  O  O21  1  0.750  0.560  0.020  1.0
  O  O22  1  0.750  0.940  0.520  1.0
  O  O23  1  0.250  0.060  0.480  1.0
  O  O24  1  0.454  0.125  0.222  1.0
  O  O25  1  0.954  0.875  0.778  1.0
  O  O26  1  0.546  0.625  0.278  1.0
  O  O27  1  0.046  0.375  0.722  1.0
  O  O28  1  0.546  0.875  0.778  1.0
  O  O29  1  0.046  0.125  0.222  1.0
  O  O30  1  0.454  0.375  0.722  1.0
  O  O31  1  0.954  0.625  0.278  1.0
  O  O32  1  0.250  0.373  0.365  1.0
  O  O33  1  0.750  0.627  0.635  1.0
  O  O34  1  0.750  0.873  0.135  1.0
  O  O35  1  0.250  0.127  0.865  1.0
[/CIF]
.