The structure described by Mg5(C2O9)2 crystallizes in the orthorhombic Cmce space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to one O(1), one O(2), one O(4), one O(5), and two equivalent O(6) atoms to form a mixture of corner and edge-sharing MgO6 octahedra. The corner-sharing octahedral tilt angles range from 53-65°. In the second Mg site, Mg(2) is bonded to two equivalent O(1) and four equivalent O(3) atoms to form corner-sharing MgO6 octahedra. The corner-sharing octahedral tilt angles are 53°. There are two inequivalent C sites. In the first C site, C(1) is bonded in a trigonal planar geometry to one O(4) and two equivalent O(3) atoms. In the second C site, C(2) is bonded in a trigonal planar geometry to one O(5) and two equivalent O(6) atoms. There are six inequivalent O sites. In the first O site, O(6) is bonded in a distorted trigonal planar geometry to two equivalent Mg(1) and one C(2) atom. In the second O site, O(1) is bonded in a trigonal planar geometry to one Mg(2) and two equivalent Mg(1) atoms. In the third O site, O(2) is bonded in a single-bond geometry to one Mg(1) atom. In the fourth O site, O(3) is bonded in a bent 150 degrees geometry to one Mg(2) and one C(1) atom. In the fifth O site, O(4) is bonded in a trigonal planar geometry to two equivalent Mg(1) and one C(1) atom. In the sixth O site, O(5) is bonded in a 3-coordinate geometry to two equivalent Mg(1) and one C(2) atom. is represented by the CIF card [CIF]
data_Mg5(C2O9)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   10.230
_cell_length_b   10.230
_cell_length_c   9.093
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   131.375
_symmetry_Int_Tables_number   1
_cell_volume   714.057
_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  0.858  0.509  0.437  1.0
  Mg  Mg1  1  0.509  0.858  0.563  1.0
  Mg  Mg2  1  0.009  0.358  0.937  1.0
  Mg  Mg3  1  0.358  0.009  0.063  1.0
  Mg  Mg4  1  0.142  0.491  0.563  1.0
  Mg  Mg5  1  0.491  0.142  0.437  1.0
  Mg  Mg6  1  0.991  0.642  0.063  1.0
  Mg  Mg7  1  0.642  0.991  0.937  1.0
  Mg  Mg8  1  0.500  0.500  0.500  1.0
  Mg  Mg9  1  0.000  0.000  0.000  1.0
  C  C10  1  0.793  0.707  0.250  1.0
  C  C11  1  0.707  0.793  0.750  1.0
  C  C12  1  0.207  0.293  0.750  1.0
  C  C13  1  0.293  0.207  0.250  1.0
  C  C14  1  0.737  0.263  0.169  1.0
  C  C15  1  0.263  0.737  0.831  1.0
  C  C16  1  0.763  0.237  0.669  1.0
  C  C17  1  0.237  0.763  0.331  1.0
  O  O18  1  0.892  0.108  1.000  1.0
  O  O19  1  0.108  0.892  0.000  1.0
  O  O20  1  0.608  0.392  0.500  1.0
  O  O21  1  0.392  0.608  0.500  1.0
  O  O22  1  0.059  0.300  0.399  1.0
  O  O23  1  0.300  0.059  0.601  1.0
  O  O24  1  0.800  0.559  0.899  1.0
  O  O25  1  0.559  0.800  0.101  1.0
  O  O26  1  0.941  0.700  0.601  1.0
  O  O27  1  0.700  0.941  0.399  1.0
  O  O28  1  0.200  0.441  0.101  1.0
  O  O29  1  0.441  0.200  0.899  1.0
  O  O30  1  0.687  0.670  0.350  1.0
  O  O31  1  0.670  0.687  0.650  1.0
  O  O32  1  0.170  0.187  0.850  1.0
  O  O33  1  0.187  0.170  0.150  1.0
  O  O34  1  0.313  0.330  0.650  1.0
  O  O35  1  0.330  0.313  0.350  1.0
  O  O36  1  0.830  0.813  0.150  1.0
  O  O37  1  0.813  0.830  0.850  1.0
  O  O38  1  0.863  0.637  0.250  1.0
  O  O39  1  0.637  0.863  0.750  1.0
  O  O40  1  0.137  0.363  0.750  1.0
  O  O41  1  0.363  0.137  0.250  1.0
  O  O42  1  0.716  0.284  0.304  1.0
  O  O43  1  0.284  0.716  0.696  1.0
  O  O44  1  0.784  0.216  0.804  1.0
  O  O45  1  0.216  0.784  0.196  1.0
  O  O46  1  0.114  0.620  0.400  1.0
  O  O47  1  0.620  0.114  0.600  1.0
  O  O48  1  0.120  0.614  0.900  1.0
  O  O49  1  0.614  0.120  0.100  1.0
  O  O50  1  0.886  0.380  0.600  1.0
  O  O51  1  0.380  0.886  0.400  1.0
  O  O52  1  0.880  0.386  0.100  1.0
  O  O53  1  0.386  0.880  0.900  1.0
[/CIF]
.
The structure described by Mg5(C2O9)2 crystallizes in the orthorhombic Cmce space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to one O(1), one O(2), one O(4), one O(5), and two equivalent O(6) atoms to form a mixture of corner and edge-sharing MgO6 octahedra. The corner-sharing octahedral tilt angles range from 53-65°. In the second Mg site, Mg(2) is bonded to two equivalent O(1) and four equivalent O(3) atoms to form corner-sharing MgO6 octahedra. The corner-sharing octahedral tilt angles are 53°. There are two inequivalent C sites. In the first C site, C(1) is bonded in a trigonal planar geometry to one O(4) and two equivalent O(3) atoms. In the second C site, C(2) is bonded in a trigonal planar geometry to one O(5) and two equivalent O(6) atoms. There are six inequivalent O sites. In the first O site, O(6) is bonded in a distorted trigonal planar geometry to two equivalent Mg(1) and one C(2) atom. In the second O site, O(1) is bonded in a trigonal planar geometry to one Mg(2) and two equivalent Mg(1) atoms. In the third O site, O(2) is bonded in a single-bond geometry to one Mg(1) atom. In the fourth O site, O(3) is bonded in a bent 150 degrees geometry to one Mg(2) and one C(1) atom. In the fifth O site, O(4) is bonded in a trigonal planar geometry to two equivalent Mg(1) and one C(1) atom. In the sixth O site, O(5) is bonded in a 3-coordinate geometry to two equivalent Mg(1) and one C(2) atom. is represented by the CIF card [CIF]
data_Mg5(C2O9)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   10.230
_cell_length_b   10.230
_cell_length_c   9.093
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   131.375
_symmetry_Int_Tables_number   1
_cell_volume   714.057
_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  0.858  0.509  0.437  1.0
  Mg  Mg1  1  0.509  0.858  0.563  1.0
  Mg  Mg2  1  0.009  0.358  0.937  1.0
  Mg  Mg3  1  0.358  0.009  0.063  1.0
  Mg  Mg4  1  0.142  0.491  0.563  1.0
  Mg  Mg5  1  0.491  0.142  0.437  1.0
  Mg  Mg6  1  0.991  0.642  0.063  1.0
  Mg  Mg7  1  0.642  0.991  0.937  1.0
  Mg  Mg8  1  0.500  0.500  0.500  1.0
  Mg  Mg9  1  0.000  0.000  0.000  1.0
  C  C10  1  0.793  0.707  0.250  1.0
  C  C11  1  0.707  0.793  0.750  1.0
  C  C12  1  0.207  0.293  0.750  1.0
  C  C13  1  0.293  0.207  0.250  1.0
  C  C14  1  0.737  0.263  0.169  1.0
  C  C15  1  0.263  0.737  0.831  1.0
  C  C16  1  0.763  0.237  0.669  1.0
  C  C17  1  0.237  0.763  0.331  1.0
  O  O18  1  0.892  0.108  1.000  1.0
  O  O19  1  0.108  0.892  0.000  1.0
  O  O20  1  0.608  0.392  0.500  1.0
  O  O21  1  0.392  0.608  0.500  1.0
  O  O22  1  0.059  0.300  0.399  1.0
  O  O23  1  0.300  0.059  0.601  1.0
  O  O24  1  0.800  0.559  0.899  1.0
  O  O25  1  0.559  0.800  0.101  1.0
  O  O26  1  0.941  0.700  0.601  1.0
  O  O27  1  0.700  0.941  0.399  1.0
  O  O28  1  0.200  0.441  0.101  1.0
  O  O29  1  0.441  0.200  0.899  1.0
  O  O30  1  0.687  0.670  0.350  1.0
  O  O31  1  0.670  0.687  0.650  1.0
  O  O32  1  0.170  0.187  0.850  1.0
  O  O33  1  0.187  0.170  0.150  1.0
  O  O34  1  0.313  0.330  0.650  1.0
  O  O35  1  0.330  0.313  0.350  1.0
  O  O36  1  0.830  0.813  0.150  1.0
  O  O37  1  0.813  0.830  0.850  1.0
  O  O38  1  0.863  0.637  0.250  1.0
  O  O39  1  0.637  0.863  0.750  1.0
  O  O40  1  0.137  0.363  0.750  1.0
  O  O41  1  0.363  0.137  0.250  1.0
  O  O42  1  0.716  0.284  0.304  1.0
  O  O43  1  0.284  0.716  0.696  1.0
  O  O44  1  0.784  0.216  0.804  1.0
  O  O45  1  0.216  0.784  0.196  1.0
  O  O46  1  0.114  0.620  0.400  1.0
  O  O47  1  0.620  0.114  0.600  1.0
  O  O48  1  0.120  0.614  0.900  1.0
  O  O49  1  0.614  0.120  0.100  1.0
  O  O50  1  0.886  0.380  0.600  1.0
  O  O51  1  0.380  0.886  0.400  1.0
  O  O52  1  0.880  0.386  0.100  1.0
  O  O53  1  0.386  0.880  0.900  1.0
[/CIF]
.