The material described by MgMn4(Si4O11)2 crystallizes in the triclinic P-1 space group. Mg(1) is bonded in a 4-coordinate geometry to two equivalent O(10) and two equivalent O(9) atoms. There are two inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to one O(1), one O(7), one O(9), and two equivalent O(11) atoms to form distorted MnO5 square pyramids that share  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(3)O4 tetrahedra,  a cornercorner with one Si(4)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra,  an edgeedge with one Mn(1)O5 square pyramid, and edges with two equivalent Mn(2)O5 square pyramids. In the second Mn site, Mn(2) is bonded to one O(11), one O(3), one O(7), one O(8), and one O(9) atom to form distorted MnO5 square pyramids that share  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(2)O4 tetrahedra,  a cornercorner with one Si(3)O4 tetrahedra, corners with two equivalent Si(4)O4 tetrahedra, and edges with two equivalent Mn(1)O5 square pyramids. There are four inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form SiO4 tetrahedra that share  a cornercorner with one Mn(1)O5 square pyramid,  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(2)O5 square pyramid, corners with two equivalent Mn(1)O5 square pyramids,  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(3)O4 tetrahedra, and  a cornercorner with one Si(4)O4 tetrahedra. 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)O5 square pyramid,  a cornercorner with one Mn(2)O5 square pyramid,  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(2)O4 tetrahedra, and  a cornercorner with one Si(4)O4 tetrahedra. In the fourth Si site, Si(4) is bonded to one O(10), one O(6), one O(8), and one O(9) atom to form SiO4 tetrahedra that share  a cornercorner with one Mn(1)O5 square pyramid, corners with two equivalent Mn(2)O5 square pyramids,  a cornercorner with one Si(2)O4 tetrahedra, and  a cornercorner with one Si(3)O4 tetrahedra. There are eleven inequivalent O sites. In the first O site, O(1) is bonded in a linear geometry to one Mn(1) and one Si(1) 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 bent 150 degrees geometry to one Mn(2) and one Si(1) atom. In the fourth O site, O(4) is bonded in a bent 120 degrees geometry to one Si(1) and one Si(2) atom. In the fifth O site, O(5) is bonded in a bent 150 degrees geometry to one Si(2) and one Si(3) atom. In the sixth O site, O(6) is bonded in a bent 120 degrees geometry to one Si(3) and one Si(4) atom. In the seventh O site, O(7) is bonded in a distorted trigonal non-coplanar geometry to one Mn(1), one Mn(2), and one Si(3) atom. In the eighth O site, O(8) is bonded in a distorted bent 120 degrees geometry to one Mn(2) and one Si(4) atom. In the ninth O site, O(9) is bonded in a distorted rectangular see-saw-like geometry to one Mg(1), one Mn(1), one Mn(2), and one Si(4) atom. In the tenth O site, O(10) is bonded in a 3-coordinate geometry to one Mg(1), one Si(2), and one Si(4) atom. In the eleventh O site, O(11) is bonded in a 4-coordinate geometry to one Mn(2), two equivalent Mn(1), and one Si(2) atom. is represented by the CIF file [CIF]
data_MgMn4(Si4O11)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.916
_cell_length_b   7.902
_cell_length_c   7.256
_cell_angle_alpha   107.627
_cell_angle_beta   105.397
_cell_angle_gamma   98.644
_symmetry_Int_Tables_number   1
_cell_volume   454.666
_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  0.500  0.000  0.000  1.0
  Mn  Mn1  1  0.360  0.591  0.881  1.0
  Mn  Mn2  1  0.402  0.623  0.353  1.0
  Mn  Mn3  1  0.598  0.377  0.647  1.0
  Mn  Mn4  1  0.640  0.409  0.119  1.0
  Si  Si5  1  0.040  0.388  0.246  1.0
  Si  Si6  1  0.215  0.230  0.964  1.0
  Si  Si7  1  0.206  0.210  0.530  1.0
  Si  Si8  1  0.638  0.974  0.746  1.0
  Si  Si9  1  0.362  0.026  0.254  1.0
  Si  Si10  1  0.794  0.790  0.470  1.0
  Si  Si11  1  0.785  0.770  0.036  1.0
  Si  Si12  1  0.960  0.612  0.754  1.0
  O  O13  1  0.131  0.570  0.799  1.0
  O  O14  1  0.060  0.265  0.397  1.0
  O  O15  1  0.191  0.571  0.339  1.0
  O  O16  1  0.060  0.249  0.033  1.0
  O  O17  1  0.170  0.159  0.718  1.0
  O  O18  1  0.239  0.024  0.382  1.0
  O  O19  1  0.373  0.376  0.623  1.0
  O  O20  1  0.472  0.808  0.629  1.0
  O  O21  1  0.419  0.841  0.154  1.0
  O  O22  1  0.292  0.069  0.033  1.0
  O  O23  1  0.365  0.420  0.079  1.0
  O  O24  1  0.635  0.580  0.921  1.0
  O  O25  1  0.708  0.931  0.967  1.0
  O  O26  1  0.581  0.159  0.846  1.0
  O  O27  1  0.528  0.192  0.371  1.0
  O  O28  1  0.627  0.624  0.377  1.0
  O  O29  1  0.761  0.976  0.618  1.0
  O  O30  1  0.830  0.841  0.282  1.0
  O  O31  1  0.940  0.751  0.967  1.0
  O  O32  1  0.809  0.429  0.661  1.0
  O  O33  1  0.940  0.735  0.603  1.0
  O  O34  1  0.869  0.430  0.201  1.0
[/CIF]
.
The material described by MgMn4(Si4O11)2 crystallizes in the triclinic P-1 space group. Mg(1) is bonded in a 4-coordinate geometry to two equivalent O(10) and two equivalent O(9) atoms. There are two inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to one O(1), one O(7), one O(9), and two equivalent O(11) atoms to form distorted MnO5 square pyramids that share  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(3)O4 tetrahedra,  a cornercorner with one Si(4)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra,  an edgeedge with one Mn(1)O5 square pyramid, and edges with two equivalent Mn(2)O5 square pyramids. In the second Mn site, Mn(2) is bonded to one O(11), one O(3), one O(7), one O(8), and one O(9) atom to form distorted MnO5 square pyramids that share  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(2)O4 tetrahedra,  a cornercorner with one Si(3)O4 tetrahedra, corners with two equivalent Si(4)O4 tetrahedra, and edges with two equivalent Mn(1)O5 square pyramids. There are four inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form SiO4 tetrahedra that share  a cornercorner with one Mn(1)O5 square pyramid,  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(2)O5 square pyramid, corners with two equivalent Mn(1)O5 square pyramids,  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(3)O4 tetrahedra, and  a cornercorner with one Si(4)O4 tetrahedra. 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)O5 square pyramid,  a cornercorner with one Mn(2)O5 square pyramid,  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(2)O4 tetrahedra, and  a cornercorner with one Si(4)O4 tetrahedra. In the fourth Si site, Si(4) is bonded to one O(10), one O(6), one O(8), and one O(9) atom to form SiO4 tetrahedra that share  a cornercorner with one Mn(1)O5 square pyramid, corners with two equivalent Mn(2)O5 square pyramids,  a cornercorner with one Si(2)O4 tetrahedra, and  a cornercorner with one Si(3)O4 tetrahedra. There are eleven inequivalent O sites. In the first O site, O(1) is bonded in a linear geometry to one Mn(1) and one Si(1) 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 bent 150 degrees geometry to one Mn(2) and one Si(1) atom. In the fourth O site, O(4) is bonded in a bent 120 degrees geometry to one Si(1) and one Si(2) atom. In the fifth O site, O(5) is bonded in a bent 150 degrees geometry to one Si(2) and one Si(3) atom. In the sixth O site, O(6) is bonded in a bent 120 degrees geometry to one Si(3) and one Si(4) atom. In the seventh O site, O(7) is bonded in a distorted trigonal non-coplanar geometry to one Mn(1), one Mn(2), and one Si(3) atom. In the eighth O site, O(8) is bonded in a distorted bent 120 degrees geometry to one Mn(2) and one Si(4) atom. In the ninth O site, O(9) is bonded in a distorted rectangular see-saw-like geometry to one Mg(1), one Mn(1), one Mn(2), and one Si(4) atom. In the tenth O site, O(10) is bonded in a 3-coordinate geometry to one Mg(1), one Si(2), and one Si(4) atom. In the eleventh O site, O(11) is bonded in a 4-coordinate geometry to one Mn(2), two equivalent Mn(1), and one Si(2) atom. is represented by the CIF file [CIF]
data_MgMn4(Si4O11)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.916
_cell_length_b   7.902
_cell_length_c   7.256
_cell_angle_alpha   107.627
_cell_angle_beta   105.397
_cell_angle_gamma   98.644
_symmetry_Int_Tables_number   1
_cell_volume   454.666
_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  0.500  0.000  0.000  1.0
  Mn  Mn1  1  0.360  0.591  0.881  1.0
  Mn  Mn2  1  0.402  0.623  0.353  1.0
  Mn  Mn3  1  0.598  0.377  0.647  1.0
  Mn  Mn4  1  0.640  0.409  0.119  1.0
  Si  Si5  1  0.040  0.388  0.246  1.0
  Si  Si6  1  0.215  0.230  0.964  1.0
  Si  Si7  1  0.206  0.210  0.530  1.0
  Si  Si8  1  0.638  0.974  0.746  1.0
  Si  Si9  1  0.362  0.026  0.254  1.0
  Si  Si10  1  0.794  0.790  0.470  1.0
  Si  Si11  1  0.785  0.770  0.036  1.0
  Si  Si12  1  0.960  0.612  0.754  1.0
  O  O13  1  0.131  0.570  0.799  1.0
  O  O14  1  0.060  0.265  0.397  1.0
  O  O15  1  0.191  0.571  0.339  1.0
  O  O16  1  0.060  0.249  0.033  1.0
  O  O17  1  0.170  0.159  0.718  1.0
  O  O18  1  0.239  0.024  0.382  1.0
  O  O19  1  0.373  0.376  0.623  1.0
  O  O20  1  0.472  0.808  0.629  1.0
  O  O21  1  0.419  0.841  0.154  1.0
  O  O22  1  0.292  0.069  0.033  1.0
  O  O23  1  0.365  0.420  0.079  1.0
  O  O24  1  0.635  0.580  0.921  1.0
  O  O25  1  0.708  0.931  0.967  1.0
  O  O26  1  0.581  0.159  0.846  1.0
  O  O27  1  0.528  0.192  0.371  1.0
  O  O28  1  0.627  0.624  0.377  1.0
  O  O29  1  0.761  0.976  0.618  1.0
  O  O30  1  0.830  0.841  0.282  1.0
  O  O31  1  0.940  0.751  0.967  1.0
  O  O32  1  0.809  0.429  0.661  1.0
  O  O33  1  0.940  0.735  0.603  1.0
  O  O34  1  0.869  0.430  0.201  1.0
[/CIF]
.