The structure described by MgMn4(Si4O11)2 crystallizes in the triclinic P1 space group. Mg(1) is bonded in a 5-coordinate geometry to one O(1), one O(21), one O(3), one O(5), and one O(8) atom. There are four inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to one O(1), one O(11), one O(12), one O(7), one O(8), and one O(9) atom to form distorted MnO6 octahedra that share  a cornercorner with one Mn(2)O5 square pyramid,  a cornercorner with one Si(2)O4 tetrahedra,  a cornercorner with one Si(3)O4 tetrahedra,  a cornercorner with one Si(4)O4 tetrahedra,  a cornercorner with one Si(5)O4 tetrahedra,  a cornercorner with one Si(7)O4 tetrahedra,  a cornercorner with one Si(8)O4 tetrahedra, and  an edgeedge with one Mn(2)O5 square pyramid. In the second Mn site, Mn(2) is bonded to one O(11), one O(16), one O(3), one O(8), and one O(9) atom to form distorted MnO5 square pyramids that share  a cornercorner with one Mn(1)O6 octahedra,  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(2)O4 tetrahedra,  a cornercorner with one Si(4)O4 tetrahedra,  a cornercorner with one Si(5)O4 tetrahedra,  a cornercorner with one Si(6)O4 tetrahedra, and  an edgeedge with one Mn(1)O6 octahedra. The corner-sharing octahedral tilt angles are 70°. In the third Mn site, Mn(3) is bonded in a 5-coordinate geometry to one O(12), one O(14), one O(15), one O(20), and one O(7) atom. In the fourth Mn site, Mn(4) is bonded in a 6-coordinate geometry to one O(11), one O(12), one O(14), one O(15), one O(16), and one O(22) atom. There are eight inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(2), one O(22), one O(3), and one O(4) atom to form SiO4 tetrahedra that share  a cornercorner with one Mn(2)O5 square pyramid,  a cornercorner with one Si(2)O4 tetrahedra, and  a cornercorner with one Si(3)O4 tetrahedra. In the second Si site, Si(2) is bonded to one O(10), one O(11), one O(4), and one O(5) atom to form SiO4 tetrahedra that share  a cornercorner with one Mn(1)O6 octahedra,  a cornercorner with one Mn(2)O5 square pyramid,  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(3)O4 tetrahedra, and  a cornercorner with one Si(5)O4 tetrahedra. The corner-sharing octahedral tilt angles are 63°. In the third Si site, Si(3) is bonded to one O(2), one O(5), one O(6), and one O(7) atom to form SiO4 tetrahedra that share  a cornercorner with one Mn(1)O6 octahedra,  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(2)O4 tetrahedra, and  a cornercorner with one Si(5)O4 tetrahedra. The corner-sharing octahedral tilt angles are 61°. In the fourth Si site, Si(4) is bonded to one O(13), one O(14), one O(17), and one O(8) atom to form SiO4 tetrahedra that share  a cornercorner with one Mn(1)O6 octahedra,  a cornercorner with one Mn(2)O5 square pyramid,  a cornercorner with one Si(6)O4 tetrahedra, and  a cornercorner with one Si(7)O4 tetrahedra. The corner-sharing octahedral tilt angles are 67°. In the fifth Si site, Si(5) is bonded to one O(10), one O(15), one O(6), and one O(9) atom to form SiO4 tetrahedra that share  a cornercorner with one Mn(1)O6 octahedra,  a cornercorner with one Mn(2)O5 square pyramid,  a cornercorner with one Si(2)O4 tetrahedra, and  a cornercorner with one Si(3)O4 tetrahedra. The corner-sharing octahedral tilt angles are 53°. In the sixth Si site, Si(6) is bonded to one O(16), one O(17), one O(18), and one O(21) atom to form SiO4 tetrahedra that share  a cornercorner with one Mn(2)O5 square pyramid,  a cornercorner with one Si(4)O4 tetrahedra,  a cornercorner with one Si(7)O4 tetrahedra, and  a cornercorner with one Si(8)O4 tetrahedra. In the seventh Si site, Si(7) is bonded to one O(12), one O(13), one O(18), and one O(19) atom to form SiO4 tetrahedra that share  a cornercorner with one Mn(1)O6 octahedra,  a cornercorner with one Si(4)O4 tetrahedra,  a cornercorner with one Si(6)O4 tetrahedra, and  a cornercorner with one Si(8)O4 tetrahedra. The corner-sharing octahedral tilt angles are 67°. In the eighth Si site, Si(8) is bonded to one O(1), one O(19), one O(20), and one O(21) atom to form SiO4 tetrahedra that share  a cornercorner with one Mn(1)O6 octahedra,  a cornercorner with one Si(6)O4 tetrahedra, and  a cornercorner with one Si(7)O4 tetrahedra. The corner-sharing octahedral tilt angles are 19°. There are twenty-two inequivalent O sites. In the first O site, O(1) is bonded in a T-shaped geometry to one Mg(1), one Mn(1), and one Si(8) atom. In the second O site, O(2) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(3) atom. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one Mg(1), one Mn(2), and one Si(1) atom. In the fourth O site, O(4) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(2) atom. In the fifth O site, O(5) is bonded in a distorted trigonal non-coplanar geometry to one Mg(1), one Si(2), and one Si(3) atom. In the sixth O site, O(6) is bonded in a distorted bent 120 degrees geometry to one Si(3) and one Si(5) atom. In the seventh O site, O(7) is bonded in a distorted trigonal planar geometry to one Mn(1), one Mn(3), and one Si(3) atom. In the eighth O site, O(8) is bonded in a distorted tetrahedral geometry to one Mg(1), one Mn(1), one Mn(2), and one Si(4) atom. In the ninth O site, O(9) is bonded in a distorted trigonal planar geometry to one Mn(1), one Mn(2), and one Si(5) atom. In the tenth O site, O(10) is bonded in a distorted bent 150 degrees geometry to one Si(2) and one Si(5) atom. In the eleventh O site, O(11) is bonded in a 4-coordinate geometry to one Mn(1), one Mn(2), one Mn(4), and one Si(2) atom. In the twelfth O site, O(12) is bonded in a 4-coordinate geometry to one Mn(1), one Mn(3), one Mn(4), and one Si(7) atom. In the thirteenth O site, O(13) is bonded in a bent 150 degrees geometry to one Si(4) and one Si(7) atom. In the fourteenth O site, O(14) is bonded in a distorted trigonal planar geometry to one Mn(3), one Mn(4), and one Si(4) atom. In the fifteenth O site, O(15) is bonded in a distorted trigonal planar geometry to one Mn(3), one Mn(4), and one Si(5) atom. In the sixteenth O site, O(16) is bonded in a distorted trigonal non-coplanar geometry to one Mn(2), one Mn(4), and one Si(6) atom. In the seventeenth O site, O(17) is bonded in a bent 150 degrees geometry to one Si(4) and one Si(6) atom. In the eighteenth O site, O(18) is bonded in a bent 150 degrees geometry to one Si(6) and one Si(7) atom. In the nineteenth O site, O(19) is bonded in a bent 120 degrees geometry to one Si(7) and one Si(8) atom. In the twentieth O site, O(20) is bonded in a bent 120 degrees geometry to one Mn(3) and one Si(8) atom. In the twenty-first O site, O(21) is bonded in a 3-coordinate geometry to one Mg(1), one Si(6), and one Si(8) atom. In the twenty-second O site, O(22) is bonded in a linear geometry to one Mn(4) and one Si(1) atom. is represented by the CIF card [CIF]
data_MgMn4(Si4O11)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.694
_cell_length_b   7.669
_cell_length_c   7.130
_cell_angle_alpha   107.418
_cell_angle_beta   103.165
_cell_angle_gamma   99.020
_symmetry_Int_Tables_number   1
_cell_volume   428.483
_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  0.186  0.806  0.603  1.0
  Mn  Mn1  1  0.392  0.626  0.879  1.0
  Mn  Mn2  1  0.394  0.638  0.345  1.0
  Mn  Mn3  1  0.609  0.374  0.643  1.0
  Mn  Mn4  1  0.619  0.372  0.128  1.0
  Si  Si5  1  0.028  0.384  0.240  1.0
  Si  Si6  1  0.226  0.218  0.956  1.0
  Si  Si7  1  0.219  0.207  0.520  1.0
  Si  Si8  1  0.605  0.980  0.779  1.0
  Si  Si9  1  0.389  0.021  0.234  1.0
  Si  Si10  1  0.775  0.787  0.470  1.0
  Si  Si11  1  0.783  0.783  0.043  1.0
  Si  Si12  1  0.968  0.627  0.765  1.0
  O  O13  1  0.154  0.625  0.772  1.0
  O  O14  1  0.064  0.252  0.386  1.0
  O  O15  1  0.156  0.590  0.346  1.0
  O  O16  1  0.070  0.272  0.025  1.0
  O  O17  1  0.175  0.129  0.701  1.0
  O  O18  1  0.269  0.020  0.386  1.0
  O  O19  1  0.378  0.386  0.612  1.0
  O  O20  1  0.431  0.820  0.678  1.0
  O  O21  1  0.431  0.817  0.176  1.0
  O  O22  1  0.281  0.043  0.020  1.0
  O  O23  1  0.383  0.401  0.054  1.0
  O  O24  1  0.640  0.585  0.918  1.0
  O  O25  1  0.713  0.950  0.981  1.0
  O  O26  1  0.581  0.195  0.846  1.0
  O  O27  1  0.542  0.207  0.346  1.0
  O  O28  1  0.632  0.590  0.381  1.0
  O  O29  1  0.705  0.951  0.606  1.0
  O  O30  1  0.827  0.847  0.291  1.0
  O  O31  1  0.950  0.760  0.983  1.0
  O  O32  1  0.833  0.429  0.671  1.0
  O  O33  1  0.942  0.762  0.613  1.0
  O  O34  1  0.844  0.406  0.199  1.0
[/CIF]
.
The structure described by MgMn4(Si4O11)2 crystallizes in the triclinic P1 space group. Mg(1) is bonded in a 5-coordinate geometry to one O(1), one O(21), one O(3), one O(5), and one O(8) atom. There are four inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to one O(1), one O(11), one O(12), one O(7), one O(8), and one O(9) atom to form distorted MnO6 octahedra that share  a cornercorner with one Mn(2)O5 square pyramid,  a cornercorner with one Si(2)O4 tetrahedra,  a cornercorner with one Si(3)O4 tetrahedra,  a cornercorner with one Si(4)O4 tetrahedra,  a cornercorner with one Si(5)O4 tetrahedra,  a cornercorner with one Si(7)O4 tetrahedra,  a cornercorner with one Si(8)O4 tetrahedra, and  an edgeedge with one Mn(2)O5 square pyramid. In the second Mn site, Mn(2) is bonded to one O(11), one O(16), one O(3), one O(8), and one O(9) atom to form distorted MnO5 square pyramids that share  a cornercorner with one Mn(1)O6 octahedra,  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(2)O4 tetrahedra,  a cornercorner with one Si(4)O4 tetrahedra,  a cornercorner with one Si(5)O4 tetrahedra,  a cornercorner with one Si(6)O4 tetrahedra, and  an edgeedge with one Mn(1)O6 octahedra. The corner-sharing octahedral tilt angles are 70°. In the third Mn site, Mn(3) is bonded in a 5-coordinate geometry to one O(12), one O(14), one O(15), one O(20), and one O(7) atom. In the fourth Mn site, Mn(4) is bonded in a 6-coordinate geometry to one O(11), one O(12), one O(14), one O(15), one O(16), and one O(22) atom. There are eight inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(2), one O(22), one O(3), and one O(4) atom to form SiO4 tetrahedra that share  a cornercorner with one Mn(2)O5 square pyramid,  a cornercorner with one Si(2)O4 tetrahedra, and  a cornercorner with one Si(3)O4 tetrahedra. In the second Si site, Si(2) is bonded to one O(10), one O(11), one O(4), and one O(5) atom to form SiO4 tetrahedra that share  a cornercorner with one Mn(1)O6 octahedra,  a cornercorner with one Mn(2)O5 square pyramid,  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(3)O4 tetrahedra, and  a cornercorner with one Si(5)O4 tetrahedra. The corner-sharing octahedral tilt angles are 63°. In the third Si site, Si(3) is bonded to one O(2), one O(5), one O(6), and one O(7) atom to form SiO4 tetrahedra that share  a cornercorner with one Mn(1)O6 octahedra,  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(2)O4 tetrahedra, and  a cornercorner with one Si(5)O4 tetrahedra. The corner-sharing octahedral tilt angles are 61°. In the fourth Si site, Si(4) is bonded to one O(13), one O(14), one O(17), and one O(8) atom to form SiO4 tetrahedra that share  a cornercorner with one Mn(1)O6 octahedra,  a cornercorner with one Mn(2)O5 square pyramid,  a cornercorner with one Si(6)O4 tetrahedra, and  a cornercorner with one Si(7)O4 tetrahedra. The corner-sharing octahedral tilt angles are 67°. In the fifth Si site, Si(5) is bonded to one O(10), one O(15), one O(6), and one O(9) atom to form SiO4 tetrahedra that share  a cornercorner with one Mn(1)O6 octahedra,  a cornercorner with one Mn(2)O5 square pyramid,  a cornercorner with one Si(2)O4 tetrahedra, and  a cornercorner with one Si(3)O4 tetrahedra. The corner-sharing octahedral tilt angles are 53°. In the sixth Si site, Si(6) is bonded to one O(16), one O(17), one O(18), and one O(21) atom to form SiO4 tetrahedra that share  a cornercorner with one Mn(2)O5 square pyramid,  a cornercorner with one Si(4)O4 tetrahedra,  a cornercorner with one Si(7)O4 tetrahedra, and  a cornercorner with one Si(8)O4 tetrahedra. In the seventh Si site, Si(7) is bonded to one O(12), one O(13), one O(18), and one O(19) atom to form SiO4 tetrahedra that share  a cornercorner with one Mn(1)O6 octahedra,  a cornercorner with one Si(4)O4 tetrahedra,  a cornercorner with one Si(6)O4 tetrahedra, and  a cornercorner with one Si(8)O4 tetrahedra. The corner-sharing octahedral tilt angles are 67°. In the eighth Si site, Si(8) is bonded to one O(1), one O(19), one O(20), and one O(21) atom to form SiO4 tetrahedra that share  a cornercorner with one Mn(1)O6 octahedra,  a cornercorner with one Si(6)O4 tetrahedra, and  a cornercorner with one Si(7)O4 tetrahedra. The corner-sharing octahedral tilt angles are 19°. There are twenty-two inequivalent O sites. In the first O site, O(1) is bonded in a T-shaped geometry to one Mg(1), one Mn(1), and one Si(8) atom. In the second O site, O(2) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(3) atom. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one Mg(1), one Mn(2), and one Si(1) atom. In the fourth O site, O(4) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(2) atom. In the fifth O site, O(5) is bonded in a distorted trigonal non-coplanar geometry to one Mg(1), one Si(2), and one Si(3) atom. In the sixth O site, O(6) is bonded in a distorted bent 120 degrees geometry to one Si(3) and one Si(5) atom. In the seventh O site, O(7) is bonded in a distorted trigonal planar geometry to one Mn(1), one Mn(3), and one Si(3) atom. In the eighth O site, O(8) is bonded in a distorted tetrahedral geometry to one Mg(1), one Mn(1), one Mn(2), and one Si(4) atom. In the ninth O site, O(9) is bonded in a distorted trigonal planar geometry to one Mn(1), one Mn(2), and one Si(5) atom. In the tenth O site, O(10) is bonded in a distorted bent 150 degrees geometry to one Si(2) and one Si(5) atom. In the eleventh O site, O(11) is bonded in a 4-coordinate geometry to one Mn(1), one Mn(2), one Mn(4), and one Si(2) atom. In the twelfth O site, O(12) is bonded in a 4-coordinate geometry to one Mn(1), one Mn(3), one Mn(4), and one Si(7) atom. In the thirteenth O site, O(13) is bonded in a bent 150 degrees geometry to one Si(4) and one Si(7) atom. In the fourteenth O site, O(14) is bonded in a distorted trigonal planar geometry to one Mn(3), one Mn(4), and one Si(4) atom. In the fifteenth O site, O(15) is bonded in a distorted trigonal planar geometry to one Mn(3), one Mn(4), and one Si(5) atom. In the sixteenth O site, O(16) is bonded in a distorted trigonal non-coplanar geometry to one Mn(2), one Mn(4), and one Si(6) atom. In the seventeenth O site, O(17) is bonded in a bent 150 degrees geometry to one Si(4) and one Si(6) atom. In the eighteenth O site, O(18) is bonded in a bent 150 degrees geometry to one Si(6) and one Si(7) atom. In the nineteenth O site, O(19) is bonded in a bent 120 degrees geometry to one Si(7) and one Si(8) atom. In the twentieth O site, O(20) is bonded in a bent 120 degrees geometry to one Mn(3) and one Si(8) atom. In the twenty-first O site, O(21) is bonded in a 3-coordinate geometry to one Mg(1), one Si(6), and one Si(8) atom. In the twenty-second O site, O(22) is bonded in a linear geometry to one Mn(4) and one Si(1) atom. is represented by the CIF card [CIF]
data_MgMn4(Si4O11)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.694
_cell_length_b   7.669
_cell_length_c   7.130
_cell_angle_alpha   107.418
_cell_angle_beta   103.165
_cell_angle_gamma   99.020
_symmetry_Int_Tables_number   1
_cell_volume   428.483
_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  0.186  0.806  0.603  1.0
  Mn  Mn1  1  0.392  0.626  0.879  1.0
  Mn  Mn2  1  0.394  0.638  0.345  1.0
  Mn  Mn3  1  0.609  0.374  0.643  1.0
  Mn  Mn4  1  0.619  0.372  0.128  1.0
  Si  Si5  1  0.028  0.384  0.240  1.0
  Si  Si6  1  0.226  0.218  0.956  1.0
  Si  Si7  1  0.219  0.207  0.520  1.0
  Si  Si8  1  0.605  0.980  0.779  1.0
  Si  Si9  1  0.389  0.021  0.234  1.0
  Si  Si10  1  0.775  0.787  0.470  1.0
  Si  Si11  1  0.783  0.783  0.043  1.0
  Si  Si12  1  0.968  0.627  0.765  1.0
  O  O13  1  0.154  0.625  0.772  1.0
  O  O14  1  0.064  0.252  0.386  1.0
  O  O15  1  0.156  0.590  0.346  1.0
  O  O16  1  0.070  0.272  0.025  1.0
  O  O17  1  0.175  0.129  0.701  1.0
  O  O18  1  0.269  0.020  0.386  1.0
  O  O19  1  0.378  0.386  0.612  1.0
  O  O20  1  0.431  0.820  0.678  1.0
  O  O21  1  0.431  0.817  0.176  1.0
  O  O22  1  0.281  0.043  0.020  1.0
  O  O23  1  0.383  0.401  0.054  1.0
  O  O24  1  0.640  0.585  0.918  1.0
  O  O25  1  0.713  0.950  0.981  1.0
  O  O26  1  0.581  0.195  0.846  1.0
  O  O27  1  0.542  0.207  0.346  1.0
  O  O28  1  0.632  0.590  0.381  1.0
  O  O29  1  0.705  0.951  0.606  1.0
  O  O30  1  0.827  0.847  0.291  1.0
  O  O31  1  0.950  0.760  0.983  1.0
  O  O32  1  0.833  0.429  0.671  1.0
  O  O33  1  0.942  0.762  0.613  1.0
  O  O34  1  0.844  0.406  0.199  1.0
[/CIF]
.