The crystal structure described by Mg5As crystallizes in the monoclinic Cm space group. There are five inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to one Mg(4), two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(3), three equivalent Mg(5), and two equivalent As(1) atoms to form distorted MgMg10As2 cuboctahedra that share corners with six equivalent Mg(1)Mg10As2 cuboctahedra, edges with six equivalent Mg(2)Mg11As cuboctahedra, faces with two equivalent Mg(1)Mg10As2 cuboctahedra, and faces with three equivalent Mg(2)Mg11As cuboctahedra. In the second Mg site, Mg(2) is bonded to two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(4), two equivalent Mg(5), three equivalent Mg(3), and one As(1) atom to form distorted MgMg11As cuboctahedra that share corners with six equivalent Mg(2)Mg11As cuboctahedra, edges with six equivalent Mg(1)Mg10As2 cuboctahedra, faces with two equivalent Mg(2)Mg11As cuboctahedra, and faces with three equivalent Mg(1)Mg10As2 cuboctahedra. In the third Mg site, Mg(3) is bonded in a 2-coordinate geometry to two equivalent Mg(1), three equivalent Mg(2), and two equivalent As(1) atoms. In the fourth Mg site, Mg(4) is bonded in a 2-coordinate geometry to one Mg(1), two equivalent Mg(2), and two equivalent As(1) atoms. In the fifth Mg site, Mg(5) is bonded in a 2-coordinate geometry to two equivalent Mg(2), three equivalent Mg(1), and two equivalent As(1) atoms. As(1) is bonded in a 9-coordinate geometry to one Mg(2), two equivalent Mg(1), two equivalent Mg(3), two equivalent Mg(4), and two equivalent Mg(5) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_Mg5As
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.042
_cell_length_b   6.042
_cell_length_c   7.428
_cell_angle_alpha   73.949
_cell_angle_beta   73.949
_cell_angle_gamma   30.166
_symmetry_Int_Tables_number   1
_cell_volume   130.551
_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
  Mg  Mg0  1  0.288  0.288  0.938  1.0
  Mg  Mg1  1  0.667  0.667  0.675  1.0
  Mg  Mg2  1  0.952  0.952  0.582  1.0
  Mg  Mg3  1  0.314  0.314  0.331  1.0
  Mg  Mg4  1  0.004  0.004  0.021  1.0
  As  As5  1  0.607  0.607  0.285  1.0
[/CIF]
.
The crystal structure described by Mg5As crystallizes in the monoclinic Cm space group. There are five inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to one Mg(4), two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(3), three equivalent Mg(5), and two equivalent As(1) atoms to form distorted MgMg10As2 cuboctahedra that share corners with six equivalent Mg(1)Mg10As2 cuboctahedra, edges with six equivalent Mg(2)Mg11As cuboctahedra, faces with two equivalent Mg(1)Mg10As2 cuboctahedra, and faces with three equivalent Mg(2)Mg11As cuboctahedra. In the second Mg site, Mg(2) is bonded to two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(4), two equivalent Mg(5), three equivalent Mg(3), and one As(1) atom to form distorted MgMg11As cuboctahedra that share corners with six equivalent Mg(2)Mg11As cuboctahedra, edges with six equivalent Mg(1)Mg10As2 cuboctahedra, faces with two equivalent Mg(2)Mg11As cuboctahedra, and faces with three equivalent Mg(1)Mg10As2 cuboctahedra. In the third Mg site, Mg(3) is bonded in a 2-coordinate geometry to two equivalent Mg(1), three equivalent Mg(2), and two equivalent As(1) atoms. In the fourth Mg site, Mg(4) is bonded in a 2-coordinate geometry to one Mg(1), two equivalent Mg(2), and two equivalent As(1) atoms. In the fifth Mg site, Mg(5) is bonded in a 2-coordinate geometry to two equivalent Mg(2), three equivalent Mg(1), and two equivalent As(1) atoms. As(1) is bonded in a 9-coordinate geometry to one Mg(2), two equivalent Mg(1), two equivalent Mg(3), two equivalent Mg(4), and two equivalent Mg(5) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_Mg5As
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.042
_cell_length_b   6.042
_cell_length_c   7.428
_cell_angle_alpha   73.949
_cell_angle_beta   73.949
_cell_angle_gamma   30.166
_symmetry_Int_Tables_number   1
_cell_volume   130.551
_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
  Mg  Mg0  1  0.288  0.288  0.938  1.0
  Mg  Mg1  1  0.667  0.667  0.675  1.0
  Mg  Mg2  1  0.952  0.952  0.582  1.0
  Mg  Mg3  1  0.314  0.314  0.331  1.0
  Mg  Mg4  1  0.004  0.004  0.021  1.0
  As  As5  1  0.607  0.607  0.285  1.0
[/CIF]
.