The crystal structure described by Mg(BH4)2 crystallizes in the orthorhombic F222 space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to four equivalent H(2) and four equivalent H(4) atoms to form distorted MgH8 hexagonal bipyramids that share edges with four equivalent B(1)H4 tetrahedra. In the second Mg site, Mg(2) is bonded in a body-centered cubic geometry to four equivalent H(1) and four equivalent H(3) atoms. B(1) is bonded to one H(1), one H(2), one H(3), and one H(4) atom to form BH4 tetrahedra that share  an edgeedge with one Mg(1)H8 hexagonal bipyramid. There are four inequivalent H sites. In the first H site, H(3) is bonded in an L-shaped geometry to one Mg(2) and one B(1) atom. In the second H site, H(4) is bonded in an L-shaped geometry to one Mg(1) and one B(1) atom. In the third H site, H(1) is bonded in an L-shaped geometry to one Mg(2) and one B(1) atom. In the fourth H site, H(2) is bonded in an L-shaped geometry to one Mg(1) and one B(1) atom. is represented by the CIF card [CIF]
data_Mg(BH4)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.538
_cell_length_b   7.538
_cell_length_c   7.752
_cell_angle_alpha   116.087
_cell_angle_beta   116.087
_cell_angle_gamma   95.485
_symmetry_Int_Tables_number   1
_cell_volume   331.747
_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  0.250  0.750  0.500  1.0
  Mg  Mg1  1  0.000  0.000  0.000  1.0
  B  B2  1  0.155  0.380  0.238  1.0
  B  B3  1  0.083  0.858  0.238  1.0
  B  B4  1  0.142  0.917  0.762  1.0
  B  B5  1  0.620  0.845  0.762  1.0
  H  H6  1  0.993  0.287  0.049  1.0
  H  H7  1  0.057  0.762  0.049  1.0
  H  H8  1  0.238  0.943  0.951  1.0
  H  H9  1  0.713  0.007  0.951  1.0
  H  H10  1  0.103  0.446  0.376  1.0
  H  H11  1  0.273  0.930  0.376  1.0
  H  H12  1  0.070  0.727  0.624  1.0
  H  H13  1  0.554  0.897  0.624  1.0
  H  H14  1  0.255  0.270  0.277  1.0
  H  H15  1  0.022  0.006  0.277  1.0
  H  H16  1  0.994  0.978  0.723  1.0
  H  H17  1  0.730  0.745  0.723  1.0
  H  H18  1  0.267  0.515  0.247  1.0
  H  H19  1  0.980  0.732  0.247  1.0
  H  H20  1  0.268  0.020  0.753  1.0
  H  H21  1  0.485  0.733  0.753  1.0
[/CIF]
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The crystal structure described by Mg(BH4)2 crystallizes in the orthorhombic F222 space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to four equivalent H(2) and four equivalent H(4) atoms to form distorted MgH8 hexagonal bipyramids that share edges with four equivalent B(1)H4 tetrahedra. In the second Mg site, Mg(2) is bonded in a body-centered cubic geometry to four equivalent H(1) and four equivalent H(3) atoms. B(1) is bonded to one H(1), one H(2), one H(3), and one H(4) atom to form BH4 tetrahedra that share  an edgeedge with one Mg(1)H8 hexagonal bipyramid. There are four inequivalent H sites. In the first H site, H(3) is bonded in an L-shaped geometry to one Mg(2) and one B(1) atom. In the second H site, H(4) is bonded in an L-shaped geometry to one Mg(1) and one B(1) atom. In the third H site, H(1) is bonded in an L-shaped geometry to one Mg(2) and one B(1) atom. In the fourth H site, H(2) is bonded in an L-shaped geometry to one Mg(1) and one B(1) atom. is represented by the CIF card [CIF]
data_Mg(BH4)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.538
_cell_length_b   7.538
_cell_length_c   7.752
_cell_angle_alpha   116.087
_cell_angle_beta   116.087
_cell_angle_gamma   95.485
_symmetry_Int_Tables_number   1
_cell_volume   331.747
_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  0.250  0.750  0.500  1.0
  Mg  Mg1  1  0.000  0.000  0.000  1.0
  B  B2  1  0.155  0.380  0.238  1.0
  B  B3  1  0.083  0.858  0.238  1.0
  B  B4  1  0.142  0.917  0.762  1.0
  B  B5  1  0.620  0.845  0.762  1.0
  H  H6  1  0.993  0.287  0.049  1.0
  H  H7  1  0.057  0.762  0.049  1.0
  H  H8  1  0.238  0.943  0.951  1.0
  H  H9  1  0.713  0.007  0.951  1.0
  H  H10  1  0.103  0.446  0.376  1.0
  H  H11  1  0.273  0.930  0.376  1.0
  H  H12  1  0.070  0.727  0.624  1.0
  H  H13  1  0.554  0.897  0.624  1.0
  H  H14  1  0.255  0.270  0.277  1.0
  H  H15  1  0.022  0.006  0.277  1.0
  H  H16  1  0.994  0.978  0.723  1.0
  H  H17  1  0.730  0.745  0.723  1.0
  H  H18  1  0.267  0.515  0.247  1.0
  H  H19  1  0.980  0.732  0.247  1.0
  H  H20  1  0.268  0.020  0.753  1.0
  H  H21  1  0.485  0.733  0.753  1.0
[/CIF]
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