The crystal structure described by Sr2Mg3H10 crystallizes in the monoclinic C2/m space group. There are two inequivalent Sr sites. In the first Sr site, Sr(1) is bonded in a 12-coordinate geometry to one H(4), two equivalent H(1), two equivalent H(8), three equivalent H(5), and four equivalent H(2) atoms. In the second Sr site, Sr(2) is bonded to one H(5), one H(6), two equivalent H(1), two equivalent H(2), two equivalent H(4), two equivalent H(7), and two equivalent H(8) atoms to form distorted SrH12 cuboctahedra that share corners with four equivalent Sr(2)H12 cuboctahedra, corners with two equivalent Mg(1)H6 octahedra,  an edgeedge with one Sr(2)H12 cuboctahedra, edges with two equivalent Mg(3)H6 octahedra, faces with two equivalent Mg(1)H6 octahedra, and faces with three equivalent Mg(2)H6 octahedra. The corner-sharing octahedral tilt angles are 47°. There are three inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to one H(3), one H(4), two equivalent H(2), and two equivalent H(7) atoms to form MgH6 octahedra that share corners with two equivalent Sr(2)H12 cuboctahedra,  a cornercorner with one Mg(2)H6 octahedra, corners with two equivalent Mg(3)H6 octahedra,  an edgeedge with one Mg(1)H6 octahedra, and faces with two equivalent Sr(2)H12 cuboctahedra. The corner-sharing octahedral tilt angles range from 9-51°. In the second Mg site, Mg(2) is bonded to one H(4), one H(5), two equivalent H(1), and two equivalent H(8) atoms to form MgH6 octahedra that share  a cornercorner with one Mg(1)H6 octahedra, corners with two equivalent Mg(2)H6 octahedra, corners with two equivalent Mg(3)H6 octahedra, and faces with three equivalent Sr(2)H12 cuboctahedra. The corner-sharing octahedral tilt angles range from 0-58°. In the third Mg site, Mg(3) is bonded to two equivalent H(1), two equivalent H(3), and two equivalent H(6) atoms to form MgH6 octahedra that share corners with two equivalent Mg(1)H6 octahedra, corners with two equivalent Mg(2)H6 octahedra, edges with two equivalent Sr(2)H12 cuboctahedra, and edges with two equivalent Mg(3)H6 octahedra. The corner-sharing octahedral tilt angles range from 51-58°. There are eight inequivalent H sites. In the first H site, H(5) is bonded in a distorted single-bond geometry to one Sr(2), three equivalent Sr(1), and one Mg(2) atom. In the second H site, H(6) is bonded in a distorted L-shaped geometry to one Sr(2) and two equivalent Mg(3) atoms. In the third H site, H(7) is bonded in a 4-coordinate geometry to two equivalent Sr(2) and two equivalent Mg(1) atoms. In the fourth H site, H(8) is bonded in a linear geometry to two equivalent Sr(1), two equivalent Sr(2), and two equivalent Mg(2) atoms. In the fifth H site, H(1) is bonded to one Sr(1), one Sr(2), one Mg(2), and one Mg(3) atom to form distorted HSr2Mg2 tetrahedra that share corners with two equivalent H(1)Sr2Mg2 tetrahedra, corners with six equivalent H(2)Sr3Mg tetrahedra, and  an edgeedge with one H(1)Sr2Mg2 tetrahedra. In the sixth H site, H(2) is bonded to one Sr(2), two equivalent Sr(1), and one Mg(1) atom to form distorted HSr3Mg tetrahedra that share corners with two equivalent H(2)Sr3Mg tetrahedra, corners with six equivalent H(1)Sr2Mg2 tetrahedra, and edges with three equivalent H(2)Sr3Mg tetrahedra. In the seventh H site, H(3) is bonded in a trigonal planar geometry to one Mg(1) and two equivalent Mg(3) atoms. In the eighth H site, H(4) is bonded in a 2-coordinate geometry to one Sr(1), two equivalent Sr(2), one Mg(1), and one Mg(2) atom. is represented by the CIF file [CIF]
data_Sr2Mg3H10
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.218
_cell_length_b   9.218
_cell_length_c   7.485
_cell_angle_alpha   69.874
_cell_angle_beta   69.874
_cell_angle_gamma   36.028
_symmetry_Int_Tables_number   1
_cell_volume   348.722
_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
  Sr  Sr0  1  0.281  0.281  0.311  1.0
  Sr  Sr1  1  0.719  0.719  0.689  1.0
  Sr  Sr2  1  0.383  0.383  0.721  1.0
  Sr  Sr3  1  0.617  0.617  0.279  1.0
  Mg  Mg4  1  0.075  0.075  0.554  1.0
  Mg  Mg5  1  0.925  0.925  0.446  1.0
  Mg  Mg6  1  0.174  0.174  0.982  1.0
  Mg  Mg7  1  0.826  0.826  0.018  1.0
  Mg  Mg8  1  0.742  0.258  0.000  1.0
  Mg  Mg9  1  0.258  0.742  0.000  1.0
  H  H10  1  0.840  0.386  0.974  1.0
  H  H11  1  0.386  0.840  0.974  1.0
  H  H12  1  0.160  0.614  0.026  1.0
  H  H13  1  0.614  0.160  0.026  1.0
  H  H14  1  0.909  0.400  0.516  1.0
  H  H15  1  0.400  0.909  0.516  1.0
  H  H16  1  0.091  0.600  0.484  1.0
  H  H17  1  0.600  0.091  0.484  1.0
  H  H18  1  0.022  0.022  0.823  1.0
  H  H19  1  0.978  0.978  0.177  1.0
  H  H20  1  0.136  0.136  0.258  1.0
  H  H21  1  0.864  0.864  0.742  1.0
  H  H22  1  0.237  0.237  0.715  1.0
  H  H23  1  0.763  0.763  0.285  1.0
  H  H24  1  0.516  0.516  0.811  1.0
  H  H25  1  0.484  0.484  0.189  1.0
  H  H26  1  0.769  0.231  0.500  1.0
  H  H27  1  0.231  0.769  0.500  1.0
  H  H28  1  0.000  0.500  0.000  1.0
  H  H29  1  0.500  0.000  0.000  1.0
[/CIF]
.
The crystal structure described by Sr2Mg3H10 crystallizes in the monoclinic C2/m space group. There are two inequivalent Sr sites. In the first Sr site, Sr(1) is bonded in a 12-coordinate geometry to one H(4), two equivalent H(1), two equivalent H(8), three equivalent H(5), and four equivalent H(2) atoms. In the second Sr site, Sr(2) is bonded to one H(5), one H(6), two equivalent H(1), two equivalent H(2), two equivalent H(4), two equivalent H(7), and two equivalent H(8) atoms to form distorted SrH12 cuboctahedra that share corners with four equivalent Sr(2)H12 cuboctahedra, corners with two equivalent Mg(1)H6 octahedra,  an edgeedge with one Sr(2)H12 cuboctahedra, edges with two equivalent Mg(3)H6 octahedra, faces with two equivalent Mg(1)H6 octahedra, and faces with three equivalent Mg(2)H6 octahedra. The corner-sharing octahedral tilt angles are 47°. There are three inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to one H(3), one H(4), two equivalent H(2), and two equivalent H(7) atoms to form MgH6 octahedra that share corners with two equivalent Sr(2)H12 cuboctahedra,  a cornercorner with one Mg(2)H6 octahedra, corners with two equivalent Mg(3)H6 octahedra,  an edgeedge with one Mg(1)H6 octahedra, and faces with two equivalent Sr(2)H12 cuboctahedra. The corner-sharing octahedral tilt angles range from 9-51°. In the second Mg site, Mg(2) is bonded to one H(4), one H(5), two equivalent H(1), and two equivalent H(8) atoms to form MgH6 octahedra that share  a cornercorner with one Mg(1)H6 octahedra, corners with two equivalent Mg(2)H6 octahedra, corners with two equivalent Mg(3)H6 octahedra, and faces with three equivalent Sr(2)H12 cuboctahedra. The corner-sharing octahedral tilt angles range from 0-58°. In the third Mg site, Mg(3) is bonded to two equivalent H(1), two equivalent H(3), and two equivalent H(6) atoms to form MgH6 octahedra that share corners with two equivalent Mg(1)H6 octahedra, corners with two equivalent Mg(2)H6 octahedra, edges with two equivalent Sr(2)H12 cuboctahedra, and edges with two equivalent Mg(3)H6 octahedra. The corner-sharing octahedral tilt angles range from 51-58°. There are eight inequivalent H sites. In the first H site, H(5) is bonded in a distorted single-bond geometry to one Sr(2), three equivalent Sr(1), and one Mg(2) atom. In the second H site, H(6) is bonded in a distorted L-shaped geometry to one Sr(2) and two equivalent Mg(3) atoms. In the third H site, H(7) is bonded in a 4-coordinate geometry to two equivalent Sr(2) and two equivalent Mg(1) atoms. In the fourth H site, H(8) is bonded in a linear geometry to two equivalent Sr(1), two equivalent Sr(2), and two equivalent Mg(2) atoms. In the fifth H site, H(1) is bonded to one Sr(1), one Sr(2), one Mg(2), and one Mg(3) atom to form distorted HSr2Mg2 tetrahedra that share corners with two equivalent H(1)Sr2Mg2 tetrahedra, corners with six equivalent H(2)Sr3Mg tetrahedra, and  an edgeedge with one H(1)Sr2Mg2 tetrahedra. In the sixth H site, H(2) is bonded to one Sr(2), two equivalent Sr(1), and one Mg(1) atom to form distorted HSr3Mg tetrahedra that share corners with two equivalent H(2)Sr3Mg tetrahedra, corners with six equivalent H(1)Sr2Mg2 tetrahedra, and edges with three equivalent H(2)Sr3Mg tetrahedra. In the seventh H site, H(3) is bonded in a trigonal planar geometry to one Mg(1) and two equivalent Mg(3) atoms. In the eighth H site, H(4) is bonded in a 2-coordinate geometry to one Sr(1), two equivalent Sr(2), one Mg(1), and one Mg(2) atom. is represented by the CIF file [CIF]
data_Sr2Mg3H10
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.218
_cell_length_b   9.218
_cell_length_c   7.485
_cell_angle_alpha   69.874
_cell_angle_beta   69.874
_cell_angle_gamma   36.028
_symmetry_Int_Tables_number   1
_cell_volume   348.722
_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
  Sr  Sr0  1  0.281  0.281  0.311  1.0
  Sr  Sr1  1  0.719  0.719  0.689  1.0
  Sr  Sr2  1  0.383  0.383  0.721  1.0
  Sr  Sr3  1  0.617  0.617  0.279  1.0
  Mg  Mg4  1  0.075  0.075  0.554  1.0
  Mg  Mg5  1  0.925  0.925  0.446  1.0
  Mg  Mg6  1  0.174  0.174  0.982  1.0
  Mg  Mg7  1  0.826  0.826  0.018  1.0
  Mg  Mg8  1  0.742  0.258  0.000  1.0
  Mg  Mg9  1  0.258  0.742  0.000  1.0
  H  H10  1  0.840  0.386  0.974  1.0
  H  H11  1  0.386  0.840  0.974  1.0
  H  H12  1  0.160  0.614  0.026  1.0
  H  H13  1  0.614  0.160  0.026  1.0
  H  H14  1  0.909  0.400  0.516  1.0
  H  H15  1  0.400  0.909  0.516  1.0
  H  H16  1  0.091  0.600  0.484  1.0
  H  H17  1  0.600  0.091  0.484  1.0
  H  H18  1  0.022  0.022  0.823  1.0
  H  H19  1  0.978  0.978  0.177  1.0
  H  H20  1  0.136  0.136  0.258  1.0
  H  H21  1  0.864  0.864  0.742  1.0
  H  H22  1  0.237  0.237  0.715  1.0
  H  H23  1  0.763  0.763  0.285  1.0
  H  H24  1  0.516  0.516  0.811  1.0
  H  H25  1  0.484  0.484  0.189  1.0
  H  H26  1  0.769  0.231  0.500  1.0
  H  H27  1  0.231  0.769  0.500  1.0
  H  H28  1  0.000  0.500  0.000  1.0
  H  H29  1  0.500  0.000  0.000  1.0
[/CIF]
.