The material described by Mn2GeSe4 is Spinel-like structured and crystallizes in the orthorhombic Pnma space group. There are two inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to one Se(2), one Se(3), and four equivalent Se(1) atoms to form MnSe6 octahedra that share corners with four equivalent Mn(1)Se6 octahedra, corners with four equivalent Mn(2)Se6 octahedra, corners with four equivalent Ge(1)Se4 tetrahedra, edges with two equivalent Mn(2)Se6 octahedra, and  an edgeedge with one Ge(1)Se4 tetrahedra. The corner-sharing octahedral tilt angles range from 47-56°. In the second Mn site, Mn(2) is bonded to two equivalent Se(1), two equivalent Se(2), and two equivalent Se(3) atoms to form MnSe6 octahedra that share corners with four equivalent Mn(1)Se6 octahedra, corners with two equivalent Ge(1)Se4 tetrahedra, edges with two equivalent Mn(1)Se6 octahedra, edges with two equivalent Mn(2)Se6 octahedra, and edges with two equivalent Ge(1)Se4 tetrahedra. The corner-sharing octahedral tilt angles range from 50-56°. Ge(1) is bonded to one Se(2), one Se(3), and two equivalent Se(1) atoms to form GeSe4 tetrahedra that share corners with two equivalent Mn(2)Se6 octahedra, corners with four equivalent Mn(1)Se6 octahedra,  an edgeedge with one Mn(1)Se6 octahedra, and edges with two equivalent Mn(2)Se6 octahedra. The corner-sharing octahedral tilt angles range from 58-62°. There are three inequivalent Se sites. In the first Se site, Se(1) is bonded in a rectangular see-saw-like geometry to one Mn(2), two equivalent Mn(1), and one Ge(1) atom. In the second Se site, Se(2) is bonded in a rectangular see-saw-like geometry to one Mn(1), two equivalent Mn(2), and one Ge(1) atom. In the third Se site, Se(3) is bonded to one Mn(1), two equivalent Mn(2), and one Ge(1) atom to form distorted corner-sharing SeMn3Ge trigonal pyramids. is represented by the CIF file [CIF]
data_Mn2GeSe4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.345
_cell_length_b   7.810
_cell_length_c   13.440
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   665.930
_cell_formula_units_Z   4
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
  Mn  Mn0  1  0.501  0.250  0.767  1.0
  Mn  Mn1  1  0.999  0.250  0.267  1.0
  Mn  Mn2  1  0.001  0.750  0.733  1.0
  Mn  Mn3  1  0.000  0.000  0.000  1.0
  Mn  Mn4  1  0.499  0.750  0.233  1.0
  Mn  Mn5  1  0.500  0.500  0.500  1.0
  Mn  Mn6  1  0.500  0.000  0.500  1.0
  Mn  Mn7  1  0.000  0.500  0.000  1.0
  Ge  Ge8  1  0.412  0.250  0.088  1.0
  Ge  Ge9  1  0.912  0.750  0.412  1.0
  Ge  Ge10  1  0.088  0.250  0.588  1.0
  Ge  Ge11  1  0.588  0.750  0.912  1.0
  Se  Se12  1  0.753  0.986  0.832  1.0
  Se  Se13  1  0.752  0.750  0.573  1.0
  Se  Se14  1  0.781  0.250  0.092  1.0
  Se  Se15  1  0.747  0.514  0.332  1.0
  Se  Se16  1  0.281  0.750  0.408  1.0
  Se  Se17  1  0.747  0.986  0.332  1.0
  Se  Se18  1  0.748  0.750  0.073  1.0
  Se  Se19  1  0.719  0.250  0.592  1.0
  Se  Se20  1  0.252  0.250  0.927  1.0
  Se  Se21  1  0.219  0.750  0.908  1.0
  Se  Se22  1  0.248  0.250  0.427  1.0
  Se  Se23  1  0.247  0.486  0.168  1.0
  Se  Se24  1  0.247  0.014  0.168  1.0
  Se  Se25  1  0.753  0.514  0.832  1.0
  Se  Se26  1  0.253  0.486  0.668  1.0
  Se  Se27  1  0.253  0.014  0.668  1.0
[/CIF]
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The material described by Mn2GeSe4 is Spinel-like structured and crystallizes in the orthorhombic Pnma space group. There are two inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to one Se(2), one Se(3), and four equivalent Se(1) atoms to form MnSe6 octahedra that share corners with four equivalent Mn(1)Se6 octahedra, corners with four equivalent Mn(2)Se6 octahedra, corners with four equivalent Ge(1)Se4 tetrahedra, edges with two equivalent Mn(2)Se6 octahedra, and  an edgeedge with one Ge(1)Se4 tetrahedra. The corner-sharing octahedral tilt angles range from 47-56°. In the second Mn site, Mn(2) is bonded to two equivalent Se(1), two equivalent Se(2), and two equivalent Se(3) atoms to form MnSe6 octahedra that share corners with four equivalent Mn(1)Se6 octahedra, corners with two equivalent Ge(1)Se4 tetrahedra, edges with two equivalent Mn(1)Se6 octahedra, edges with two equivalent Mn(2)Se6 octahedra, and edges with two equivalent Ge(1)Se4 tetrahedra. The corner-sharing octahedral tilt angles range from 50-56°. Ge(1) is bonded to one Se(2), one Se(3), and two equivalent Se(1) atoms to form GeSe4 tetrahedra that share corners with two equivalent Mn(2)Se6 octahedra, corners with four equivalent Mn(1)Se6 octahedra,  an edgeedge with one Mn(1)Se6 octahedra, and edges with two equivalent Mn(2)Se6 octahedra. The corner-sharing octahedral tilt angles range from 58-62°. There are three inequivalent Se sites. In the first Se site, Se(1) is bonded in a rectangular see-saw-like geometry to one Mn(2), two equivalent Mn(1), and one Ge(1) atom. In the second Se site, Se(2) is bonded in a rectangular see-saw-like geometry to one Mn(1), two equivalent Mn(2), and one Ge(1) atom. In the third Se site, Se(3) is bonded to one Mn(1), two equivalent Mn(2), and one Ge(1) atom to form distorted corner-sharing SeMn3Ge trigonal pyramids. is represented by the CIF file [CIF]
data_Mn2GeSe4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.345
_cell_length_b   7.810
_cell_length_c   13.440
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   665.930
_cell_formula_units_Z   4
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
  Mn  Mn0  1  0.501  0.250  0.767  1.0
  Mn  Mn1  1  0.999  0.250  0.267  1.0
  Mn  Mn2  1  0.001  0.750  0.733  1.0
  Mn  Mn3  1  0.000  0.000  0.000  1.0
  Mn  Mn4  1  0.499  0.750  0.233  1.0
  Mn  Mn5  1  0.500  0.500  0.500  1.0
  Mn  Mn6  1  0.500  0.000  0.500  1.0
  Mn  Mn7  1  0.000  0.500  0.000  1.0
  Ge  Ge8  1  0.412  0.250  0.088  1.0
  Ge  Ge9  1  0.912  0.750  0.412  1.0
  Ge  Ge10  1  0.088  0.250  0.588  1.0
  Ge  Ge11  1  0.588  0.750  0.912  1.0
  Se  Se12  1  0.753  0.986  0.832  1.0
  Se  Se13  1  0.752  0.750  0.573  1.0
  Se  Se14  1  0.781  0.250  0.092  1.0
  Se  Se15  1  0.747  0.514  0.332  1.0
  Se  Se16  1  0.281  0.750  0.408  1.0
  Se  Se17  1  0.747  0.986  0.332  1.0
  Se  Se18  1  0.748  0.750  0.073  1.0
  Se  Se19  1  0.719  0.250  0.592  1.0
  Se  Se20  1  0.252  0.250  0.927  1.0
  Se  Se21  1  0.219  0.750  0.908  1.0
  Se  Se22  1  0.248  0.250  0.427  1.0
  Se  Se23  1  0.247  0.486  0.168  1.0
  Se  Se24  1  0.247  0.014  0.168  1.0
  Se  Se25  1  0.753  0.514  0.832  1.0
  Se  Se26  1  0.253  0.486  0.668  1.0
  Se  Se27  1  0.253  0.014  0.668  1.0
[/CIF]
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