The material described by MgCoSiO5 crystallizes in the triclinic P1 space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to one O(10), one O(2), one O(3), one O(4), one O(7), and one O(8) atom to form distorted MgO6 pentagonal pyramids that share  a cornercorner with one Co(2)O6 octahedra,  a cornercorner with one Si(1)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra,  an edgeedge with one Co(2)O6 octahedra, edges with two equivalent Co(1)O6 octahedra,  an edgeedge with one Mg(2)O6 pentagonal pyramid, and  an edgeedge with one Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 45°. In the second Mg site, Mg(2) is bonded to one O(1), one O(2), one O(4), one O(5), one O(6), and one O(9) atom to form distorted MgO6 pentagonal pyramids that share  a cornercorner with one Co(2)O6 octahedra,  a cornercorner with one Si(2)O4 tetrahedra, corners with two equivalent Si(1)O4 tetrahedra,  an edgeedge with one Co(2)O6 octahedra, edges with two equivalent Co(1)O6 octahedra,  an edgeedge with one Mg(1)O6 pentagonal pyramid, and  an edgeedge with one Si(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 45°. There are two inequivalent Co sites. In the first Co site, Co(1) is bonded to one O(10), one O(2), one O(4), one O(5), one O(7), and one O(9) atom to form CoO6 octahedra that share corners with two equivalent Co(2)O6 octahedra, corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, edges with two equivalent Mg(1)O6 pentagonal pyramids, and edges with two equivalent Mg(2)O6 pentagonal pyramids. The corner-sharing octahedral tilt angles are 42°. In the second Co site, Co(2) is bonded to one O(1), one O(10), one O(3), one O(6), one O(8), and one O(9) atom to form CoO6 octahedra that share corners with two equivalent Co(1)O6 octahedra,  a cornercorner with one Mg(1)O6 pentagonal pyramid,  a cornercorner with one Mg(2)O6 pentagonal pyramid, corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra,  an edgeedge with one Mg(1)O6 pentagonal pyramid, and  an edgeedge with one Mg(2)O6 pentagonal pyramid. The corner-sharing octahedral tilt angles are 42°. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(1), one O(2), one O(7), and one O(8) atom to form SiO4 tetrahedra that share corners with two equivalent Co(1)O6 octahedra, corners with two equivalent Co(2)O6 octahedra,  a cornercorner with one Mg(1)O6 pentagonal pyramid, corners with two equivalent Mg(2)O6 pentagonal pyramids, and  an edgeedge with one Mg(1)O6 pentagonal pyramid. The corner-sharing octahedral tilt angles range from 30-55°. In the second Si site, Si(2) is bonded to one O(3), one O(4), one O(5), and one O(6) atom to form SiO4 tetrahedra that share corners with two equivalent Co(1)O6 octahedra, corners with two equivalent Co(2)O6 octahedra,  a cornercorner with one Mg(2)O6 pentagonal pyramid, corners with two equivalent Mg(1)O6 pentagonal pyramids, and  an edgeedge with one Mg(2)O6 pentagonal pyramid. The corner-sharing octahedral tilt angles range from 30-55°. There are ten inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one Mg(2), one Co(2), and one Si(1) atom. In the second O site, O(2) is bonded in a distorted rectangular see-saw-like geometry to one Mg(1), one Mg(2), one Co(1), and one Si(1) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Mg(1), one Co(2), and one Si(2) atom. In the fourth O site, O(4) is bonded in a distorted rectangular see-saw-like geometry to one Mg(1), one Mg(2), one Co(1), and one Si(2) atom. In the fifth O site, O(5) is bonded in a distorted T-shaped geometry to one Mg(2), one Co(1), and one Si(2) atom. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to one Mg(2), one Co(2), and one Si(2) atom. In the seventh O site, O(7) is bonded in a distorted T-shaped geometry to one Mg(1), one Co(1), and one Si(1) atom. In the eighth O site, O(8) is bonded in a distorted trigonal planar geometry to one Mg(1), one Co(2), and one Si(1) atom. In the ninth O site, O(9) is bonded in a distorted trigonal non-coplanar geometry to one Mg(2), one Co(1), and one Co(2) atom. In the tenth O site, O(10) is bonded in a distorted trigonal non-coplanar geometry to one Mg(1), one Co(1), and one Co(2) atom. is represented by the CIF card [CIF]
data_MgCoSiO5
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.472
_cell_length_b   6.798
_cell_length_c   8.348
_cell_angle_alpha   90.274
_cell_angle_beta   38.787
_cell_angle_gamma   73.521
_symmetry_Int_Tables_number   1
_cell_volume   172.866
_cell_formula_units_Z   2
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  0.387  0.255  0.740  1.0
  Mg  Mg1  1  0.612  0.717  0.252  1.0
  Co  Co2  1  0.499  0.485  0.996  1.0
  Co  Co3  1  0.499  0.985  0.996  1.0
  Si  Si4  1  0.551  0.231  0.318  1.0
  Si  Si5  1  0.447  0.740  0.674  1.0
  O  O6  1  0.523  0.034  0.229  1.0
  O  O7  1  0.691  0.392  0.140  1.0
  O  O8  1  0.473  0.938  0.763  1.0
  O  O9  1  0.308  0.580  0.852  1.0
  O  O10  1  0.897  0.591  0.338  1.0
  O  O11  1  0.127  0.830  0.676  1.0
  O  O12  1  0.102  0.379  0.654  1.0
  O  O13  1  0.872  0.140  0.315  1.0
  O  O14  1  0.457  0.745  0.094  1.0
  O  O15  1  0.543  0.225  0.897  1.0
[/CIF]
.
The material described by MgCoSiO5 crystallizes in the triclinic P1 space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to one O(10), one O(2), one O(3), one O(4), one O(7), and one O(8) atom to form distorted MgO6 pentagonal pyramids that share  a cornercorner with one Co(2)O6 octahedra,  a cornercorner with one Si(1)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra,  an edgeedge with one Co(2)O6 octahedra, edges with two equivalent Co(1)O6 octahedra,  an edgeedge with one Mg(2)O6 pentagonal pyramid, and  an edgeedge with one Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 45°. In the second Mg site, Mg(2) is bonded to one O(1), one O(2), one O(4), one O(5), one O(6), and one O(9) atom to form distorted MgO6 pentagonal pyramids that share  a cornercorner with one Co(2)O6 octahedra,  a cornercorner with one Si(2)O4 tetrahedra, corners with two equivalent Si(1)O4 tetrahedra,  an edgeedge with one Co(2)O6 octahedra, edges with two equivalent Co(1)O6 octahedra,  an edgeedge with one Mg(1)O6 pentagonal pyramid, and  an edgeedge with one Si(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 45°. There are two inequivalent Co sites. In the first Co site, Co(1) is bonded to one O(10), one O(2), one O(4), one O(5), one O(7), and one O(9) atom to form CoO6 octahedra that share corners with two equivalent Co(2)O6 octahedra, corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, edges with two equivalent Mg(1)O6 pentagonal pyramids, and edges with two equivalent Mg(2)O6 pentagonal pyramids. The corner-sharing octahedral tilt angles are 42°. In the second Co site, Co(2) is bonded to one O(1), one O(10), one O(3), one O(6), one O(8), and one O(9) atom to form CoO6 octahedra that share corners with two equivalent Co(1)O6 octahedra,  a cornercorner with one Mg(1)O6 pentagonal pyramid,  a cornercorner with one Mg(2)O6 pentagonal pyramid, corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra,  an edgeedge with one Mg(1)O6 pentagonal pyramid, and  an edgeedge with one Mg(2)O6 pentagonal pyramid. The corner-sharing octahedral tilt angles are 42°. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(1), one O(2), one O(7), and one O(8) atom to form SiO4 tetrahedra that share corners with two equivalent Co(1)O6 octahedra, corners with two equivalent Co(2)O6 octahedra,  a cornercorner with one Mg(1)O6 pentagonal pyramid, corners with two equivalent Mg(2)O6 pentagonal pyramids, and  an edgeedge with one Mg(1)O6 pentagonal pyramid. The corner-sharing octahedral tilt angles range from 30-55°. In the second Si site, Si(2) is bonded to one O(3), one O(4), one O(5), and one O(6) atom to form SiO4 tetrahedra that share corners with two equivalent Co(1)O6 octahedra, corners with two equivalent Co(2)O6 octahedra,  a cornercorner with one Mg(2)O6 pentagonal pyramid, corners with two equivalent Mg(1)O6 pentagonal pyramids, and  an edgeedge with one Mg(2)O6 pentagonal pyramid. The corner-sharing octahedral tilt angles range from 30-55°. There are ten inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one Mg(2), one Co(2), and one Si(1) atom. In the second O site, O(2) is bonded in a distorted rectangular see-saw-like geometry to one Mg(1), one Mg(2), one Co(1), and one Si(1) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Mg(1), one Co(2), and one Si(2) atom. In the fourth O site, O(4) is bonded in a distorted rectangular see-saw-like geometry to one Mg(1), one Mg(2), one Co(1), and one Si(2) atom. In the fifth O site, O(5) is bonded in a distorted T-shaped geometry to one Mg(2), one Co(1), and one Si(2) atom. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to one Mg(2), one Co(2), and one Si(2) atom. In the seventh O site, O(7) is bonded in a distorted T-shaped geometry to one Mg(1), one Co(1), and one Si(1) atom. In the eighth O site, O(8) is bonded in a distorted trigonal planar geometry to one Mg(1), one Co(2), and one Si(1) atom. In the ninth O site, O(9) is bonded in a distorted trigonal non-coplanar geometry to one Mg(2), one Co(1), and one Co(2) atom. In the tenth O site, O(10) is bonded in a distorted trigonal non-coplanar geometry to one Mg(1), one Co(1), and one Co(2) atom. is represented by the CIF card [CIF]
data_MgCoSiO5
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.472
_cell_length_b   6.798
_cell_length_c   8.348
_cell_angle_alpha   90.274
_cell_angle_beta   38.787
_cell_angle_gamma   73.521
_symmetry_Int_Tables_number   1
_cell_volume   172.866
_cell_formula_units_Z   2
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  0.387  0.255  0.740  1.0
  Mg  Mg1  1  0.612  0.717  0.252  1.0
  Co  Co2  1  0.499  0.485  0.996  1.0
  Co  Co3  1  0.499  0.985  0.996  1.0
  Si  Si4  1  0.551  0.231  0.318  1.0
  Si  Si5  1  0.447  0.740  0.674  1.0
  O  O6  1  0.523  0.034  0.229  1.0
  O  O7  1  0.691  0.392  0.140  1.0
  O  O8  1  0.473  0.938  0.763  1.0
  O  O9  1  0.308  0.580  0.852  1.0
  O  O10  1  0.897  0.591  0.338  1.0
  O  O11  1  0.127  0.830  0.676  1.0
  O  O12  1  0.102  0.379  0.654  1.0
  O  O13  1  0.872  0.140  0.315  1.0
  O  O14  1  0.457  0.745  0.094  1.0
  O  O15  1  0.543  0.225  0.897  1.0
[/CIF]
.