The material described by MgMn4(HO4)2 crystallizes in the triclinic P1 space group. Mg(1) is bonded to one O(3), one O(8), two equivalent O(1), and two equivalent O(5) atoms to form MgO6 octahedra that share corners with two equivalent Mn(4)O6 octahedra, edges with two equivalent Mg(1)O6 octahedra, and  a faceface with one Mn(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 39-42°. There are four inequivalent Mn sites. In the first Mn site, Mn(1) is bonded in a 6-coordinate geometry to one O(1), one O(5), two equivalent O(3), and two equivalent O(8) atoms. In the second Mn site, Mn(2) is bonded to one O(2), one O(6), two equivalent O(4), and two equivalent O(7) atoms to form edge-sharing MnO6 octahedra. In the third Mn site, Mn(3) is bonded in a 6-coordinate geometry to one O(3), one O(7), two equivalent O(1), and two equivalent O(6) atoms. In the fourth Mn site, Mn(4) is bonded to one O(4), one O(8), two equivalent O(2), and two equivalent O(5) atoms to form distorted MnO6 octahedra that share corners with two equivalent Mg(1)O6 octahedra, edges with two equivalent Mn(2)O6 octahedra, edges with two equivalent Mn(4)O6 octahedra, and  a faceface with one Mg(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 39-42°. There are two inequivalent H sites. In the first H site, H(1) is bonded in a single-bond geometry to one O(1) atom. In the second H site, H(2) is bonded in a single-bond geometry to one O(2) atom. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a distorted single-bond geometry to two equivalent Mg(1), one Mn(1), two equivalent Mn(3), and one H(1) atom. In the second O site, O(2) is bonded in a distorted rectangular see-saw-like geometry to one Mn(2), two equivalent Mn(4), and one H(2) atom. In the third O site, O(3) is bonded to one Mg(1), one Mn(3), and two equivalent Mn(1) atoms to form distorted OMgMn3 tetrahedra that share corners with two equivalent O(3)MgMn3 tetrahedra, corners with three equivalent O(8)MgMn3 trigonal pyramids, edges with two equivalent O(5)Mg2Mn3 trigonal bipyramids, and  an edgeedge with one O(8)MgMn3 trigonal pyramid. In the fourth O site, O(4) is bonded in a trigonal non-coplanar geometry to one Mn(4) and two equivalent Mn(2) atoms. In the fifth O site, O(5) is bonded to two equivalent Mg(1), one Mn(1), and two equivalent Mn(4) atoms to form distorted OMg2Mn3 trigonal bipyramids that share corners with two equivalent O(8)MgMn3 trigonal pyramids, edges with two equivalent O(3)MgMn3 tetrahedra, edges with two equivalent O(5)Mg2Mn3 trigonal bipyramids, and edges with two equivalent O(8)MgMn3 trigonal pyramids. In the sixth O site, O(6) is bonded in a trigonal planar geometry to one Mn(2) and two equivalent Mn(3) atoms. In the seventh O site, O(7) is bonded in a trigonal planar geometry to one Mn(3) and two equivalent Mn(2) atoms. In the eighth O site, O(8) is bonded to one Mg(1), one Mn(4), and two equivalent Mn(1) atoms to form OMgMn3 trigonal pyramids that share corners with three equivalent O(3)MgMn3 tetrahedra, corners with two equivalent O(5)Mg2Mn3 trigonal bipyramids, corners with two equivalent O(8)MgMn3 trigonal pyramids,  an edgeedge with one O(3)MgMn3 tetrahedra, and edges with two equivalent O(5)Mg2Mn3 trigonal bipyramids. is represented by the CIF file [CIF]
data_MgMn4(HO4)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.895
_cell_length_b   3.031
_cell_length_c   5.183
_cell_angle_alpha   88.953
_cell_angle_beta   89.848
_cell_angle_gamma   91.516
_symmetry_Int_Tables_number   1
_cell_volume   155.348
_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  0.597  0.814  0.969  1.0
  Mn  Mn1  1  0.655  0.305  0.457  1.0
  Mn  Mn2  1  0.141  0.241  0.039  1.0
  Mn  Mn3  1  0.344  0.751  0.535  1.0
  Mn  Mn4  1  0.874  0.747  0.923  1.0
  H  H5  1  0.400  0.292  0.950  1.0
  H  H6  1  0.005  0.175  0.567  1.0
  O  O7  1  0.475  0.309  0.823  1.0
  O  O8  1  0.985  0.217  0.750  1.0
  O  O9  1  0.536  0.800  0.340  1.0
  O  O10  1  0.024  0.724  0.170  1.0
  O  O11  1  0.745  0.326  0.089  1.0
  O  O12  1  0.267  0.243  0.339  1.0
  O  O13  1  0.233  0.756  0.869  1.0
  O  O14  1  0.731  0.801  0.654  1.0
[/CIF]
.
The material described by MgMn4(HO4)2 crystallizes in the triclinic P1 space group. Mg(1) is bonded to one O(3), one O(8), two equivalent O(1), and two equivalent O(5) atoms to form MgO6 octahedra that share corners with two equivalent Mn(4)O6 octahedra, edges with two equivalent Mg(1)O6 octahedra, and  a faceface with one Mn(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 39-42°. There are four inequivalent Mn sites. In the first Mn site, Mn(1) is bonded in a 6-coordinate geometry to one O(1), one O(5), two equivalent O(3), and two equivalent O(8) atoms. In the second Mn site, Mn(2) is bonded to one O(2), one O(6), two equivalent O(4), and two equivalent O(7) atoms to form edge-sharing MnO6 octahedra. In the third Mn site, Mn(3) is bonded in a 6-coordinate geometry to one O(3), one O(7), two equivalent O(1), and two equivalent O(6) atoms. In the fourth Mn site, Mn(4) is bonded to one O(4), one O(8), two equivalent O(2), and two equivalent O(5) atoms to form distorted MnO6 octahedra that share corners with two equivalent Mg(1)O6 octahedra, edges with two equivalent Mn(2)O6 octahedra, edges with two equivalent Mn(4)O6 octahedra, and  a faceface with one Mg(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 39-42°. There are two inequivalent H sites. In the first H site, H(1) is bonded in a single-bond geometry to one O(1) atom. In the second H site, H(2) is bonded in a single-bond geometry to one O(2) atom. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a distorted single-bond geometry to two equivalent Mg(1), one Mn(1), two equivalent Mn(3), and one H(1) atom. In the second O site, O(2) is bonded in a distorted rectangular see-saw-like geometry to one Mn(2), two equivalent Mn(4), and one H(2) atom. In the third O site, O(3) is bonded to one Mg(1), one Mn(3), and two equivalent Mn(1) atoms to form distorted OMgMn3 tetrahedra that share corners with two equivalent O(3)MgMn3 tetrahedra, corners with three equivalent O(8)MgMn3 trigonal pyramids, edges with two equivalent O(5)Mg2Mn3 trigonal bipyramids, and  an edgeedge with one O(8)MgMn3 trigonal pyramid. In the fourth O site, O(4) is bonded in a trigonal non-coplanar geometry to one Mn(4) and two equivalent Mn(2) atoms. In the fifth O site, O(5) is bonded to two equivalent Mg(1), one Mn(1), and two equivalent Mn(4) atoms to form distorted OMg2Mn3 trigonal bipyramids that share corners with two equivalent O(8)MgMn3 trigonal pyramids, edges with two equivalent O(3)MgMn3 tetrahedra, edges with two equivalent O(5)Mg2Mn3 trigonal bipyramids, and edges with two equivalent O(8)MgMn3 trigonal pyramids. In the sixth O site, O(6) is bonded in a trigonal planar geometry to one Mn(2) and two equivalent Mn(3) atoms. In the seventh O site, O(7) is bonded in a trigonal planar geometry to one Mn(3) and two equivalent Mn(2) atoms. In the eighth O site, O(8) is bonded to one Mg(1), one Mn(4), and two equivalent Mn(1) atoms to form OMgMn3 trigonal pyramids that share corners with three equivalent O(3)MgMn3 tetrahedra, corners with two equivalent O(5)Mg2Mn3 trigonal bipyramids, corners with two equivalent O(8)MgMn3 trigonal pyramids,  an edgeedge with one O(3)MgMn3 tetrahedra, and edges with two equivalent O(5)Mg2Mn3 trigonal bipyramids. is represented by the CIF file [CIF]
data_MgMn4(HO4)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.895
_cell_length_b   3.031
_cell_length_c   5.183
_cell_angle_alpha   88.953
_cell_angle_beta   89.848
_cell_angle_gamma   91.516
_symmetry_Int_Tables_number   1
_cell_volume   155.348
_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  0.597  0.814  0.969  1.0
  Mn  Mn1  1  0.655  0.305  0.457  1.0
  Mn  Mn2  1  0.141  0.241  0.039  1.0
  Mn  Mn3  1  0.344  0.751  0.535  1.0
  Mn  Mn4  1  0.874  0.747  0.923  1.0
  H  H5  1  0.400  0.292  0.950  1.0
  H  H6  1  0.005  0.175  0.567  1.0
  O  O7  1  0.475  0.309  0.823  1.0
  O  O8  1  0.985  0.217  0.750  1.0
  O  O9  1  0.536  0.800  0.340  1.0
  O  O10  1  0.024  0.724  0.170  1.0
  O  O11  1  0.745  0.326  0.089  1.0
  O  O12  1  0.267  0.243  0.339  1.0
  O  O13  1  0.233  0.756  0.869  1.0
  O  O14  1  0.731  0.801  0.654  1.0
[/CIF]
.