The material described by Mn2Si(H2O3)2 crystallizes in the orthorhombic Pca2_1 space group. There are two inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to one O(2), one O(4), two equivalent O(1), and two equivalent O(3) atoms to form MnO6 octahedra that share  a cornercorner with one Mn(2)O6 octahedra, corners with two equivalent Si(1)O4 tetrahedra, edges with two equivalent Mn(1)O6 octahedra, and edges with three equivalent Mn(2)O6 octahedra. The corner-sharing octahedral tilt angles are 55°. In the second Mn site, Mn(2) is bonded to one O(1), one O(3), one O(4), one O(5), and two equivalent O(2) atoms to form distorted MnO6 octahedra that share  a cornercorner with one Mn(1)O6 octahedra, corners with two equivalent Mn(2)O6 octahedra, corners with two equivalent Si(1)O4 tetrahedra, and edges with three equivalent Mn(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 55-56°. Si(1) is bonded to one O(1), one O(5), and two equivalent O(6) atoms to form SiO4 tetrahedra that share corners with two equivalent Mn(1)O6 octahedra, corners with two equivalent Mn(2)O6 octahedra, and corners with two equivalent Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 58-62°. There are four inequivalent H sites. In the first H site, H(1) is bonded in a single-bond geometry to one O(2) atom. In the second H site, H(2) is bonded in a single-bond geometry to one O(3) atom. In the third H site, H(3) is bonded in a linear geometry to one O(4) and one O(5) atom. In the fourth H site, H(4) is bonded in a distorted single-bond geometry to one O(4) and one O(5) atom. There are six inequivalent O sites. In the first O site, O(2) is bonded in a distorted single-bond geometry to one Mn(1), two equivalent Mn(2), and one H(1) atom. In the second O site, O(3) is bonded in a distorted single-bond geometry to one Mn(2), two equivalent Mn(1), and one H(2) atom. In the third O site, O(4) is bonded in a distorted water-like geometry to one Mn(1), one Mn(2), one H(3), and one H(4) atom. In the fourth O site, O(5) is bonded in a distorted tetrahedral geometry to one Mn(2), one Si(1), one H(3), and one H(4) atom. In the fifth O site, O(6) is bonded in a bent 150 degrees geometry to two equivalent Si(1) atoms. In the sixth O site, O(1) is bonded in a 4-coordinate geometry to one Mn(2), two equivalent Mn(1), and one Si(1) atom. is represented by the CIF card [CIF]
data_Mn2Si(H2O3)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.412
_cell_length_b   7.303
_cell_length_c   12.887
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   509.387
_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
  Mn  Mn0  1  1.000  0.176  0.688  1.0
  Mn  Mn1  1  0.500  0.824  0.312  1.0
  Mn  Mn2  1  0.500  0.176  0.812  1.0
  Mn  Mn3  1  1.000  0.824  0.188  1.0
  Mn  Mn4  1  0.979  0.830  0.459  1.0
  Mn  Mn5  1  0.479  0.170  0.541  1.0
  Mn  Mn6  1  0.479  0.830  0.041  1.0
  Mn  Mn7  1  0.979  0.170  0.959  1.0
  Si  Si8  1  0.185  0.215  0.314  1.0
  Si  Si9  1  0.685  0.785  0.686  1.0
  Si  Si10  1  0.685  0.215  0.186  1.0
  Si  Si11  1  0.185  0.785  0.814  1.0
  H  H12  1  0.749  0.110  0.381  1.0
  H  H13  1  0.249  0.890  0.619  1.0
  H  H14  1  0.249  0.110  0.119  1.0
  H  H15  1  0.749  0.890  0.881  1.0
  H  H16  1  0.352  0.548  0.183  1.0
  H  H17  1  0.852  0.452  0.817  1.0
  H  H18  1  0.852  0.548  0.317  1.0
  H  H19  1  0.352  0.452  0.683  1.0
  H  H20  1  0.299  0.520  0.435  1.0
  H  H21  1  0.799  0.480  0.565  1.0
  H  H22  1  0.799  0.520  0.065  1.0
  H  H23  1  0.299  0.480  0.935  1.0
  H  H24  1  0.472  0.666  0.500  1.0
  H  H25  1  0.972  0.334  0.500  1.0
  H  H26  1  0.972  0.666  0.000  1.0
  H  H27  1  0.472  0.334  1.000  1.0
  O  O28  1  0.173  0.992  0.318  1.0
  O  O29  1  0.673  0.008  0.682  1.0
  O  O30  1  0.673  0.992  0.182  1.0
  O  O31  1  0.173  0.008  0.818  1.0
  O  O32  1  0.674  0.017  0.425  1.0
  O  O33  1  0.174  0.983  0.575  1.0
  O  O34  1  0.174  0.017  0.075  1.0
  O  O35  1  0.674  0.983  0.925  1.0
  O  O36  1  0.347  0.682  0.177  1.0
  O  O37  1  0.847  0.318  0.823  1.0
  O  O38  1  0.847  0.682  0.323  1.0
  O  O39  1  0.347  0.318  0.677  1.0
  O  O40  1  0.335  0.657  0.447  1.0
  O  O41  1  0.835  0.343  0.553  1.0
  O  O42  1  0.835  0.657  0.053  1.0
  O  O43  1  0.335  0.343  0.947  1.0
  O  O44  1  0.228  0.312  0.426  1.0
  O  O45  1  0.728  0.688  0.574  1.0
  O  O46  1  0.728  0.312  0.074  1.0
  O  O47  1  0.228  0.688  0.926  1.0
  O  O48  1  0.908  0.285  0.268  1.0
  O  O49  1  0.408  0.715  0.732  1.0
  O  O50  1  0.408  0.285  0.232  1.0
  O  O51  1  0.908  0.715  0.768  1.0
[/CIF]
.
The material described by Mn2Si(H2O3)2 crystallizes in the orthorhombic Pca2_1 space group. There are two inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to one O(2), one O(4), two equivalent O(1), and two equivalent O(3) atoms to form MnO6 octahedra that share  a cornercorner with one Mn(2)O6 octahedra, corners with two equivalent Si(1)O4 tetrahedra, edges with two equivalent Mn(1)O6 octahedra, and edges with three equivalent Mn(2)O6 octahedra. The corner-sharing octahedral tilt angles are 55°. In the second Mn site, Mn(2) is bonded to one O(1), one O(3), one O(4), one O(5), and two equivalent O(2) atoms to form distorted MnO6 octahedra that share  a cornercorner with one Mn(1)O6 octahedra, corners with two equivalent Mn(2)O6 octahedra, corners with two equivalent Si(1)O4 tetrahedra, and edges with three equivalent Mn(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 55-56°. Si(1) is bonded to one O(1), one O(5), and two equivalent O(6) atoms to form SiO4 tetrahedra that share corners with two equivalent Mn(1)O6 octahedra, corners with two equivalent Mn(2)O6 octahedra, and corners with two equivalent Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 58-62°. There are four inequivalent H sites. In the first H site, H(1) is bonded in a single-bond geometry to one O(2) atom. In the second H site, H(2) is bonded in a single-bond geometry to one O(3) atom. In the third H site, H(3) is bonded in a linear geometry to one O(4) and one O(5) atom. In the fourth H site, H(4) is bonded in a distorted single-bond geometry to one O(4) and one O(5) atom. There are six inequivalent O sites. In the first O site, O(2) is bonded in a distorted single-bond geometry to one Mn(1), two equivalent Mn(2), and one H(1) atom. In the second O site, O(3) is bonded in a distorted single-bond geometry to one Mn(2), two equivalent Mn(1), and one H(2) atom. In the third O site, O(4) is bonded in a distorted water-like geometry to one Mn(1), one Mn(2), one H(3), and one H(4) atom. In the fourth O site, O(5) is bonded in a distorted tetrahedral geometry to one Mn(2), one Si(1), one H(3), and one H(4) atom. In the fifth O site, O(6) is bonded in a bent 150 degrees geometry to two equivalent Si(1) atoms. In the sixth O site, O(1) is bonded in a 4-coordinate geometry to one Mn(2), two equivalent Mn(1), and one Si(1) atom. is represented by the CIF card [CIF]
data_Mn2Si(H2O3)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.412
_cell_length_b   7.303
_cell_length_c   12.887
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   509.387
_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
  Mn  Mn0  1  1.000  0.176  0.688  1.0
  Mn  Mn1  1  0.500  0.824  0.312  1.0
  Mn  Mn2  1  0.500  0.176  0.812  1.0
  Mn  Mn3  1  1.000  0.824  0.188  1.0
  Mn  Mn4  1  0.979  0.830  0.459  1.0
  Mn  Mn5  1  0.479  0.170  0.541  1.0
  Mn  Mn6  1  0.479  0.830  0.041  1.0
  Mn  Mn7  1  0.979  0.170  0.959  1.0
  Si  Si8  1  0.185  0.215  0.314  1.0
  Si  Si9  1  0.685  0.785  0.686  1.0
  Si  Si10  1  0.685  0.215  0.186  1.0
  Si  Si11  1  0.185  0.785  0.814  1.0
  H  H12  1  0.749  0.110  0.381  1.0
  H  H13  1  0.249  0.890  0.619  1.0
  H  H14  1  0.249  0.110  0.119  1.0
  H  H15  1  0.749  0.890  0.881  1.0
  H  H16  1  0.352  0.548  0.183  1.0
  H  H17  1  0.852  0.452  0.817  1.0
  H  H18  1  0.852  0.548  0.317  1.0
  H  H19  1  0.352  0.452  0.683  1.0
  H  H20  1  0.299  0.520  0.435  1.0
  H  H21  1  0.799  0.480  0.565  1.0
  H  H22  1  0.799  0.520  0.065  1.0
  H  H23  1  0.299  0.480  0.935  1.0
  H  H24  1  0.472  0.666  0.500  1.0
  H  H25  1  0.972  0.334  0.500  1.0
  H  H26  1  0.972  0.666  0.000  1.0
  H  H27  1  0.472  0.334  1.000  1.0
  O  O28  1  0.173  0.992  0.318  1.0
  O  O29  1  0.673  0.008  0.682  1.0
  O  O30  1  0.673  0.992  0.182  1.0
  O  O31  1  0.173  0.008  0.818  1.0
  O  O32  1  0.674  0.017  0.425  1.0
  O  O33  1  0.174  0.983  0.575  1.0
  O  O34  1  0.174  0.017  0.075  1.0
  O  O35  1  0.674  0.983  0.925  1.0
  O  O36  1  0.347  0.682  0.177  1.0
  O  O37  1  0.847  0.318  0.823  1.0
  O  O38  1  0.847  0.682  0.323  1.0
  O  O39  1  0.347  0.318  0.677  1.0
  O  O40  1  0.335  0.657  0.447  1.0
  O  O41  1  0.835  0.343  0.553  1.0
  O  O42  1  0.835  0.657  0.053  1.0
  O  O43  1  0.335  0.343  0.947  1.0
  O  O44  1  0.228  0.312  0.426  1.0
  O  O45  1  0.728  0.688  0.574  1.0
  O  O46  1  0.728  0.312  0.074  1.0
  O  O47  1  0.228  0.688  0.926  1.0
  O  O48  1  0.908  0.285  0.268  1.0
  O  O49  1  0.408  0.715  0.732  1.0
  O  O50  1  0.408  0.285  0.232  1.0
  O  O51  1  0.908  0.715  0.768  1.0
[/CIF]
.