The compound described by La2Mn(SeO)2 crystallizes in the monoclinic Cc space group. There are four inequivalent La sites. In the first La site, La(1) is bonded in a 3-coordinate geometry to one Se(1), two equivalent Se(2), two equivalent Se(3), one O(2), and two equivalent O(3) atoms. In the second La site, La(2) is bonded in a 3-coordinate geometry to one Se(1), two equivalent Se(2), two equivalent Se(3), one O(1), and two equivalent O(4) atoms. In the third La site, La(3) is bonded in a 4-coordinate geometry to two equivalent Se(2), two equivalent Se(4), one O(1), one O(3), and two equivalent O(2) atoms. In the fourth La site, La(4) is bonded in a 4-coordinate geometry to two equivalent Se(3), two equivalent Se(4), one O(2), one O(4), and two equivalent O(1) atoms. There are two inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to one Se(3), one Se(4), and two equivalent Se(1) atoms to form distorted corner-sharing MnSe4 trigonal pyramids. In the second Mn site, Mn(2) is bonded in a distorted linear geometry to two equivalent Se(1), two equivalent Se(4), one O(3), and one O(4) atom. There are four inequivalent Se sites. In the first Se site, Se(1) is bonded in a 6-coordinate geometry to one La(1), one La(2), two equivalent Mn(1), and two equivalent Mn(2) atoms. In the second Se site, Se(2) is bonded in a 6-coordinate geometry to two equivalent La(1), two equivalent La(2), and two equivalent La(3) atoms. In the third Se site, Se(3) is bonded in a 7-coordinate geometry to two equivalent La(1), two equivalent La(2), two equivalent La(4), and one Mn(1) atom. In the fourth Se site, Se(4) is bonded in a 7-coordinate geometry to two equivalent La(3), two equivalent La(4), one Mn(1), and two equivalent Mn(2) atoms. There are four inequivalent O sites. In the first O site, O(1) is bonded to one La(2), one La(3), and two equivalent La(4) atoms to form OLa4 tetrahedra that share  a cornercorner with one O(3)La3Mn tetrahedra, corners with two equivalent O(1)La4 tetrahedra, edges with two equivalent O(4)La3Mn tetrahedra, and edges with two equivalent O(2)La4 tetrahedra. In the second O site, O(2) is bonded to one La(1), one La(4), and two equivalent La(3) atoms to form OLa4 tetrahedra that share  a cornercorner with one O(4)La3Mn tetrahedra, corners with two equivalent O(2)La4 tetrahedra, edges with two equivalent O(3)La3Mn tetrahedra, and edges with two equivalent O(1)La4 tetrahedra. In the third O site, O(3) is bonded to one La(3), two equivalent La(1), and one Mn(2) atom to form OLa3Mn tetrahedra that share  a cornercorner with one O(4)La3Mn tetrahedra,  a cornercorner with one O(1)La4 tetrahedra, corners with two equivalent O(3)La3Mn tetrahedra, and edges with two equivalent O(2)La4 tetrahedra. In the fourth O site, O(4) is bonded to one La(4), two equivalent La(2), and one Mn(2) atom to form OLa3Mn tetrahedra that share  a cornercorner with one O(3)La3Mn tetrahedra,  a cornercorner with one O(2)La4 tetrahedra, corners with two equivalent O(4)La3Mn tetrahedra, and edges with two equivalent O(1)La4 tetrahedra. is represented by the Crystallographic Information File (CIF) [CIF]
data_La2Mn(SeO)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.571
_cell_length_b   8.571
_cell_length_c   17.751
_cell_angle_alpha   89.994
_cell_angle_beta   89.994
_cell_angle_gamma   152.754
_symmetry_Int_Tables_number   1
_cell_volume   596.944
_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
  La  La0  1  0.424  0.576  0.914  1.0
  La  La1  1  0.577  0.423  0.084  1.0
  La  La2  1  0.423  0.577  0.584  1.0
  La  La3  1  0.576  0.424  0.414  1.0
  La  La4  1  0.731  0.272  0.910  1.0
  La  La5  1  0.269  0.733  0.088  1.0
  La  La6  1  0.733  0.269  0.588  1.0
  La  La7  1  0.272  0.731  0.410  1.0
  Mn  Mn8  1  0.082  0.913  0.725  1.0
  Mn  Mn9  1  0.913  0.082  0.225  1.0
  Mn  Mn10  1  0.886  0.164  0.750  1.0
  Mn  Mn11  1  0.164  0.886  0.250  1.0
  Se  Se12  1  0.488  0.508  0.750  1.0
  Se  Se13  1  0.508  0.488  0.250  1.0
  Se  Se14  1  0.079  0.923  0.933  1.0
  Se  Se15  1  0.921  0.080  0.073  1.0
  Se  Se16  1  0.080  0.921  0.573  1.0
  Se  Se17  1  0.923  0.079  0.433  1.0
  Se  Se18  1  0.245  0.770  0.750  1.0
  Se  Se19  1  0.770  0.245  0.250  1.0
  O  O20  1  0.291  0.712  0.544  1.0
  O  O21  1  0.711  0.292  0.455  1.0
  O  O22  1  0.292  0.711  0.955  1.0
  O  O23  1  0.712  0.291  0.044  1.0
  O  O24  1  0.871  0.132  0.865  1.0
  O  O25  1  0.133  0.870  0.135  1.0
  O  O26  1  0.870  0.133  0.635  1.0
  O  O27  1  0.132  0.871  0.365  1.0
[/CIF]
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The compound described by La2Mn(SeO)2 crystallizes in the monoclinic Cc space group. There are four inequivalent La sites. In the first La site, La(1) is bonded in a 3-coordinate geometry to one Se(1), two equivalent Se(2), two equivalent Se(3), one O(2), and two equivalent O(3) atoms. In the second La site, La(2) is bonded in a 3-coordinate geometry to one Se(1), two equivalent Se(2), two equivalent Se(3), one O(1), and two equivalent O(4) atoms. In the third La site, La(3) is bonded in a 4-coordinate geometry to two equivalent Se(2), two equivalent Se(4), one O(1), one O(3), and two equivalent O(2) atoms. In the fourth La site, La(4) is bonded in a 4-coordinate geometry to two equivalent Se(3), two equivalent Se(4), one O(2), one O(4), and two equivalent O(1) atoms. There are two inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to one Se(3), one Se(4), and two equivalent Se(1) atoms to form distorted corner-sharing MnSe4 trigonal pyramids. In the second Mn site, Mn(2) is bonded in a distorted linear geometry to two equivalent Se(1), two equivalent Se(4), one O(3), and one O(4) atom. There are four inequivalent Se sites. In the first Se site, Se(1) is bonded in a 6-coordinate geometry to one La(1), one La(2), two equivalent Mn(1), and two equivalent Mn(2) atoms. In the second Se site, Se(2) is bonded in a 6-coordinate geometry to two equivalent La(1), two equivalent La(2), and two equivalent La(3) atoms. In the third Se site, Se(3) is bonded in a 7-coordinate geometry to two equivalent La(1), two equivalent La(2), two equivalent La(4), and one Mn(1) atom. In the fourth Se site, Se(4) is bonded in a 7-coordinate geometry to two equivalent La(3), two equivalent La(4), one Mn(1), and two equivalent Mn(2) atoms. There are four inequivalent O sites. In the first O site, O(1) is bonded to one La(2), one La(3), and two equivalent La(4) atoms to form OLa4 tetrahedra that share  a cornercorner with one O(3)La3Mn tetrahedra, corners with two equivalent O(1)La4 tetrahedra, edges with two equivalent O(4)La3Mn tetrahedra, and edges with two equivalent O(2)La4 tetrahedra. In the second O site, O(2) is bonded to one La(1), one La(4), and two equivalent La(3) atoms to form OLa4 tetrahedra that share  a cornercorner with one O(4)La3Mn tetrahedra, corners with two equivalent O(2)La4 tetrahedra, edges with two equivalent O(3)La3Mn tetrahedra, and edges with two equivalent O(1)La4 tetrahedra. In the third O site, O(3) is bonded to one La(3), two equivalent La(1), and one Mn(2) atom to form OLa3Mn tetrahedra that share  a cornercorner with one O(4)La3Mn tetrahedra,  a cornercorner with one O(1)La4 tetrahedra, corners with two equivalent O(3)La3Mn tetrahedra, and edges with two equivalent O(2)La4 tetrahedra. In the fourth O site, O(4) is bonded to one La(4), two equivalent La(2), and one Mn(2) atom to form OLa3Mn tetrahedra that share  a cornercorner with one O(3)La3Mn tetrahedra,  a cornercorner with one O(2)La4 tetrahedra, corners with two equivalent O(4)La3Mn tetrahedra, and edges with two equivalent O(1)La4 tetrahedra. is represented by the Crystallographic Information File (CIF) [CIF]
data_La2Mn(SeO)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.571
_cell_length_b   8.571
_cell_length_c   17.751
_cell_angle_alpha   89.994
_cell_angle_beta   89.994
_cell_angle_gamma   152.754
_symmetry_Int_Tables_number   1
_cell_volume   596.944
_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
  La  La0  1  0.424  0.576  0.914  1.0
  La  La1  1  0.577  0.423  0.084  1.0
  La  La2  1  0.423  0.577  0.584  1.0
  La  La3  1  0.576  0.424  0.414  1.0
  La  La4  1  0.731  0.272  0.910  1.0
  La  La5  1  0.269  0.733  0.088  1.0
  La  La6  1  0.733  0.269  0.588  1.0
  La  La7  1  0.272  0.731  0.410  1.0
  Mn  Mn8  1  0.082  0.913  0.725  1.0
  Mn  Mn9  1  0.913  0.082  0.225  1.0
  Mn  Mn10  1  0.886  0.164  0.750  1.0
  Mn  Mn11  1  0.164  0.886  0.250  1.0
  Se  Se12  1  0.488  0.508  0.750  1.0
  Se  Se13  1  0.508  0.488  0.250  1.0
  Se  Se14  1  0.079  0.923  0.933  1.0
  Se  Se15  1  0.921  0.080  0.073  1.0
  Se  Se16  1  0.080  0.921  0.573  1.0
  Se  Se17  1  0.923  0.079  0.433  1.0
  Se  Se18  1  0.245  0.770  0.750  1.0
  Se  Se19  1  0.770  0.245  0.250  1.0
  O  O20  1  0.291  0.712  0.544  1.0
  O  O21  1  0.711  0.292  0.455  1.0
  O  O22  1  0.292  0.711  0.955  1.0
  O  O23  1  0.712  0.291  0.044  1.0
  O  O24  1  0.871  0.132  0.865  1.0
  O  O25  1  0.133  0.870  0.135  1.0
  O  O26  1  0.870  0.133  0.635  1.0
  O  O27  1  0.132  0.871  0.365  1.0
[/CIF]
.