The material structure described by Ca4MgB4H6(CO9)2 crystallizes in the monoclinic C2/m space group. Ca(1) is bonded in a 8-coordinate geometry to one O(1), one O(2), one O(3), one O(5), one O(6), and three equivalent O(4) atoms. Mg(1) is bonded to two equivalent O(1) and four equivalent O(2) atoms to form MgO6 octahedra that share corners with two equivalent B(2)O4 tetrahedra, corners with four equivalent B(1)O4 tetrahedra, and edges with two equivalent B(2)O4 tetrahedra. There are two inequivalent B sites. In the first B site, B(1) is bonded to two equivalent O(2) and two equivalent O(3) atoms to form BO4 tetrahedra that share corners with two equivalent Mg(1)O6 octahedra and corners with two equivalent B(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 69°. In the second B site, B(2) is bonded to one O(1), one O(5), and two equivalent O(2) atoms to form BO4 tetrahedra that share  a cornercorner with one Mg(1)O6 octahedra, corners with two equivalent B(1)O4 tetrahedra, and  an edgeedge with one Mg(1)O6 octahedra. The corner-sharing octahedral tilt angles are 63°. C(1) is bonded in a trigonal planar geometry to one O(6) and two equivalent O(4) atoms. There are two inequivalent H sites. In the first H site, H(1) is bonded in a single-bond geometry to one O(3) atom. In the second H site, H(2) is bonded in a single-bond geometry to one O(5) atom. There are six inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Ca(1), one Mg(1), and one B(2) atom to form distorted corner-sharing OCa2MgB tetrahedra. In the second O site, O(2) is bonded in a 4-coordinate geometry to one Ca(1), one Mg(1), one B(1), and one B(2) atom. In the third O site, O(3) is bonded in a distorted water-like geometry to one Ca(1), one B(1), and one H(1) atom. In the fourth O site, O(4) is bonded in a distorted single-bond geometry to three equivalent Ca(1) and one C(1) atom. In the fifth O site, O(5) is bonded in a distorted water-like geometry to two equivalent Ca(1), one B(2), and one H(2) atom. In the sixth O site, O(6) is bonded in a distorted single-bond geometry to two equivalent Ca(1) and one C(1) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Ca4MgB4H6(CO9)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.966
_cell_length_b   9.966
_cell_length_c   4.524
_cell_angle_alpha   79.236
_cell_angle_beta   79.236
_cell_angle_gamma   51.830
_symmetry_Int_Tables_number   1
_cell_volume   345.577
_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
  Ca  Ca0  1  0.925  0.387  0.841  1.0
  Ca  Ca1  1  0.387  0.925  0.841  1.0
  Ca  Ca2  1  0.075  0.613  0.159  1.0
  Ca  Ca3  1  0.613  0.075  0.159  1.0
  Mg  Mg4  1  0.000  0.000  0.000  1.0
  B  B5  1  0.776  0.224  0.500  1.0
  B  B6  1  0.224  0.776  0.500  1.0
  B  B7  1  0.097  0.097  0.381  1.0
  B  B8  1  0.903  0.903  0.619  1.0
  H  H9  1  0.619  0.393  0.794  1.0
  H  H10  1  0.393  0.619  0.794  1.0
  H  H11  1  0.381  0.607  0.206  1.0
  H  H12  1  0.607  0.381  0.206  1.0
  H  H13  1  0.213  0.213  0.301  1.0
  H  H14  1  0.787  0.787  0.699  1.0
  C  C15  1  0.305  0.305  0.751  1.0
  C  C16  1  0.695  0.695  0.249  1.0
  O  O17  1  0.101  0.101  0.689  1.0
  O  O18  1  0.899  0.899  0.311  1.0
  O  O19  1  0.920  0.192  0.280  1.0
  O  O20  1  0.192  0.920  0.280  1.0
  O  O21  1  0.080  0.808  0.720  1.0
  O  O22  1  0.808  0.080  0.720  1.0
  O  O23  1  0.723  0.365  0.674  1.0
  O  O24  1  0.365  0.723  0.674  1.0
  O  O25  1  0.277  0.635  0.326  1.0
  O  O26  1  0.635  0.277  0.326  1.0
  O  O27  1  0.846  0.585  0.351  1.0
  O  O28  1  0.585  0.846  0.351  1.0
  O  O29  1  0.154  0.415  0.649  1.0
  O  O30  1  0.415  0.154  0.649  1.0
  O  O31  1  0.175  0.175  0.176  1.0
  O  O32  1  0.825  0.825  0.824  1.0
  O  O33  1  0.343  0.343  0.965  1.0
  O  O34  1  0.657  0.657  0.035  1.0
[/CIF]
.
The material structure described by Ca4MgB4H6(CO9)2 crystallizes in the monoclinic C2/m space group. Ca(1) is bonded in a 8-coordinate geometry to one O(1), one O(2), one O(3), one O(5), one O(6), and three equivalent O(4) atoms. Mg(1) is bonded to two equivalent O(1) and four equivalent O(2) atoms to form MgO6 octahedra that share corners with two equivalent B(2)O4 tetrahedra, corners with four equivalent B(1)O4 tetrahedra, and edges with two equivalent B(2)O4 tetrahedra. There are two inequivalent B sites. In the first B site, B(1) is bonded to two equivalent O(2) and two equivalent O(3) atoms to form BO4 tetrahedra that share corners with two equivalent Mg(1)O6 octahedra and corners with two equivalent B(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 69°. In the second B site, B(2) is bonded to one O(1), one O(5), and two equivalent O(2) atoms to form BO4 tetrahedra that share  a cornercorner with one Mg(1)O6 octahedra, corners with two equivalent B(1)O4 tetrahedra, and  an edgeedge with one Mg(1)O6 octahedra. The corner-sharing octahedral tilt angles are 63°. C(1) is bonded in a trigonal planar geometry to one O(6) and two equivalent O(4) atoms. There are two inequivalent H sites. In the first H site, H(1) is bonded in a single-bond geometry to one O(3) atom. In the second H site, H(2) is bonded in a single-bond geometry to one O(5) atom. There are six inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Ca(1), one Mg(1), and one B(2) atom to form distorted corner-sharing OCa2MgB tetrahedra. In the second O site, O(2) is bonded in a 4-coordinate geometry to one Ca(1), one Mg(1), one B(1), and one B(2) atom. In the third O site, O(3) is bonded in a distorted water-like geometry to one Ca(1), one B(1), and one H(1) atom. In the fourth O site, O(4) is bonded in a distorted single-bond geometry to three equivalent Ca(1) and one C(1) atom. In the fifth O site, O(5) is bonded in a distorted water-like geometry to two equivalent Ca(1), one B(2), and one H(2) atom. In the sixth O site, O(6) is bonded in a distorted single-bond geometry to two equivalent Ca(1) and one C(1) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Ca4MgB4H6(CO9)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.966
_cell_length_b   9.966
_cell_length_c   4.524
_cell_angle_alpha   79.236
_cell_angle_beta   79.236
_cell_angle_gamma   51.830
_symmetry_Int_Tables_number   1
_cell_volume   345.577
_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
  Ca  Ca0  1  0.925  0.387  0.841  1.0
  Ca  Ca1  1  0.387  0.925  0.841  1.0
  Ca  Ca2  1  0.075  0.613  0.159  1.0
  Ca  Ca3  1  0.613  0.075  0.159  1.0
  Mg  Mg4  1  0.000  0.000  0.000  1.0
  B  B5  1  0.776  0.224  0.500  1.0
  B  B6  1  0.224  0.776  0.500  1.0
  B  B7  1  0.097  0.097  0.381  1.0
  B  B8  1  0.903  0.903  0.619  1.0
  H  H9  1  0.619  0.393  0.794  1.0
  H  H10  1  0.393  0.619  0.794  1.0
  H  H11  1  0.381  0.607  0.206  1.0
  H  H12  1  0.607  0.381  0.206  1.0
  H  H13  1  0.213  0.213  0.301  1.0
  H  H14  1  0.787  0.787  0.699  1.0
  C  C15  1  0.305  0.305  0.751  1.0
  C  C16  1  0.695  0.695  0.249  1.0
  O  O17  1  0.101  0.101  0.689  1.0
  O  O18  1  0.899  0.899  0.311  1.0
  O  O19  1  0.920  0.192  0.280  1.0
  O  O20  1  0.192  0.920  0.280  1.0
  O  O21  1  0.080  0.808  0.720  1.0
  O  O22  1  0.808  0.080  0.720  1.0
  O  O23  1  0.723  0.365  0.674  1.0
  O  O24  1  0.365  0.723  0.674  1.0
  O  O25  1  0.277  0.635  0.326  1.0
  O  O26  1  0.635  0.277  0.326  1.0
  O  O27  1  0.846  0.585  0.351  1.0
  O  O28  1  0.585  0.846  0.351  1.0
  O  O29  1  0.154  0.415  0.649  1.0
  O  O30  1  0.415  0.154  0.649  1.0
  O  O31  1  0.175  0.175  0.176  1.0
  O  O32  1  0.825  0.825  0.824  1.0
  O  O33  1  0.343  0.343  0.965  1.0
  O  O34  1  0.657  0.657  0.035  1.0
[/CIF]
.