The compound described by RbAsSe2 crystallizes in the monoclinic C2/c space group. There are three inequivalent Rb sites. In the first Rb site, Rb(1) is bonded in a 8-coordinate geometry to two equivalent As(2), two equivalent Se(4), and four equivalent Se(3) atoms. In the second Rb site, Rb(2) is bonded in a 6-coordinate geometry to two equivalent Se(3) and four equivalent Se(1) atoms. In the third Rb site, Rb(3) is bonded in a 7-coordinate geometry to one As(1), two equivalent Se(1), two equivalent Se(2), and two equivalent Se(4) atoms. There are two inequivalent As sites. In the first As site, As(1) is bonded in a 3-coordinate geometry to one Rb(3), one Se(2), one Se(3), and one Se(4) atom. In the second As site, As(2) is bonded in a 4-coordinate geometry to one Rb(1), one Se(1), one Se(2), and one Se(4) atom. There are four inequivalent Se sites. In the first Se site, Se(1) is bonded to two equivalent Rb(2), two equivalent Rb(3), and one As(2) atom to form SeRb4As trigonal bipyramids that share corners with three equivalent Se(4)Rb3As2 square pyramids, corners with two equivalent Se(1)Rb4As trigonal bipyramids, corners with three equivalent Se(2)Rb2As2 trigonal pyramids,  an edgeedge with one Se(4)Rb3As2 square pyramid, edges with three equivalent Se(1)Rb4As trigonal bipyramids, and  an edgeedge with one Se(2)Rb2As2 trigonal pyramid. In the second Se site, Se(2) is bonded to two equivalent Rb(3), one As(1), and one As(2) atom to form distorted SeRb2As2 trigonal pyramids that share corners with four equivalent Se(4)Rb3As2 square pyramids, corners with three equivalent Se(1)Rb4As trigonal bipyramids, corners with two equivalent Se(2)Rb2As2 trigonal pyramids,  an edgeedge with one Se(4)Rb3As2 square pyramid, and  an edgeedge with one Se(1)Rb4As trigonal bipyramid. In the third Se site, Se(3) is bonded in a 4-coordinate geometry to one Rb(2), two equivalent Rb(1), and one As(1) atom. In the fourth Se site, Se(4) is bonded to one Rb(1), two equivalent Rb(3), one As(1), and one As(2) atom to form distorted SeRb3As2 square pyramids that share  a cornercorner with one Se(4)Rb3As2 square pyramid, corners with three equivalent Se(1)Rb4As trigonal bipyramids, corners with four equivalent Se(2)Rb2As2 trigonal pyramids,  an edgeedge with one Se(4)Rb3As2 square pyramid,  an edgeedge with one Se(1)Rb4As trigonal bipyramid, and  an edgeedge with one Se(2)Rb2As2 trigonal pyramid. is represented by the Crystallographic Information File (CIF) [CIF]
data_RbAsSe2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   12.823
_cell_length_b   12.823
_cell_length_c   9.556
_cell_angle_alpha   78.639
_cell_angle_beta   78.639
_cell_angle_gamma   46.027
_symmetry_Int_Tables_number   1
_cell_volume   1104.552
_cell_formula_units_Z   8
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
  Rb  Rb0  1  0.463  0.537  0.750  1.0
  Rb  Rb1  1  0.537  0.463  0.250  1.0
  Rb  Rb2  1  0.002  0.998  0.750  1.0
  Rb  Rb3  1  0.998  0.002  0.250  1.0
  Rb  Rb4  1  0.123  0.274  0.171  1.0
  Rb  Rb5  1  0.726  0.877  0.329  1.0
  Rb  Rb6  1  0.877  0.726  0.829  1.0
  Rb  Rb7  1  0.274  0.123  0.671  1.0
  As  As8  1  0.510  0.795  0.956  1.0
  As  As9  1  0.807  0.411  0.851  1.0
  As  As10  1  0.589  0.193  0.649  1.0
  As  As11  1  0.193  0.589  0.149  1.0
  As  As12  1  0.411  0.807  0.351  1.0
  As  As13  1  0.205  0.490  0.544  1.0
  As  As14  1  0.490  0.205  0.044  1.0
  As  As15  1  0.795  0.510  0.456  1.0
  Se  Se16  1  0.190  0.016  0.442  1.0
  Se  Se17  1  0.984  0.810  0.058  1.0
  Se  Se18  1  0.810  0.984  0.558  1.0
  Se  Se19  1  0.911  0.479  0.656  1.0
  Se  Se20  1  0.016  0.190  0.942  1.0
  Se  Se21  1  0.479  0.911  0.156  1.0
  Se  Se22  1  0.089  0.521  0.344  1.0
  Se  Se23  1  0.521  0.089  0.844  1.0
  Se  Se24  1  0.777  0.340  0.507  1.0
  Se  Se25  1  0.660  0.223  0.993  1.0
  Se  Se26  1  0.223  0.660  0.493  1.0
  Se  Se27  1  0.340  0.777  0.007  1.0
  Se  Se28  1  0.558  0.744  0.536  1.0
  Se  Se29  1  0.256  0.442  0.964  1.0
  Se  Se30  1  0.442  0.256  0.464  1.0
  Se  Se31  1  0.744  0.558  0.036  1.0
[/CIF]
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The compound described by RbAsSe2 crystallizes in the monoclinic C2/c space group. There are three inequivalent Rb sites. In the first Rb site, Rb(1) is bonded in a 8-coordinate geometry to two equivalent As(2), two equivalent Se(4), and four equivalent Se(3) atoms. In the second Rb site, Rb(2) is bonded in a 6-coordinate geometry to two equivalent Se(3) and four equivalent Se(1) atoms. In the third Rb site, Rb(3) is bonded in a 7-coordinate geometry to one As(1), two equivalent Se(1), two equivalent Se(2), and two equivalent Se(4) atoms. There are two inequivalent As sites. In the first As site, As(1) is bonded in a 3-coordinate geometry to one Rb(3), one Se(2), one Se(3), and one Se(4) atom. In the second As site, As(2) is bonded in a 4-coordinate geometry to one Rb(1), one Se(1), one Se(2), and one Se(4) atom. There are four inequivalent Se sites. In the first Se site, Se(1) is bonded to two equivalent Rb(2), two equivalent Rb(3), and one As(2) atom to form SeRb4As trigonal bipyramids that share corners with three equivalent Se(4)Rb3As2 square pyramids, corners with two equivalent Se(1)Rb4As trigonal bipyramids, corners with three equivalent Se(2)Rb2As2 trigonal pyramids,  an edgeedge with one Se(4)Rb3As2 square pyramid, edges with three equivalent Se(1)Rb4As trigonal bipyramids, and  an edgeedge with one Se(2)Rb2As2 trigonal pyramid. In the second Se site, Se(2) is bonded to two equivalent Rb(3), one As(1), and one As(2) atom to form distorted SeRb2As2 trigonal pyramids that share corners with four equivalent Se(4)Rb3As2 square pyramids, corners with three equivalent Se(1)Rb4As trigonal bipyramids, corners with two equivalent Se(2)Rb2As2 trigonal pyramids,  an edgeedge with one Se(4)Rb3As2 square pyramid, and  an edgeedge with one Se(1)Rb4As trigonal bipyramid. In the third Se site, Se(3) is bonded in a 4-coordinate geometry to one Rb(2), two equivalent Rb(1), and one As(1) atom. In the fourth Se site, Se(4) is bonded to one Rb(1), two equivalent Rb(3), one As(1), and one As(2) atom to form distorted SeRb3As2 square pyramids that share  a cornercorner with one Se(4)Rb3As2 square pyramid, corners with three equivalent Se(1)Rb4As trigonal bipyramids, corners with four equivalent Se(2)Rb2As2 trigonal pyramids,  an edgeedge with one Se(4)Rb3As2 square pyramid,  an edgeedge with one Se(1)Rb4As trigonal bipyramid, and  an edgeedge with one Se(2)Rb2As2 trigonal pyramid. is represented by the Crystallographic Information File (CIF) [CIF]
data_RbAsSe2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   12.823
_cell_length_b   12.823
_cell_length_c   9.556
_cell_angle_alpha   78.639
_cell_angle_beta   78.639
_cell_angle_gamma   46.027
_symmetry_Int_Tables_number   1
_cell_volume   1104.552
_cell_formula_units_Z   8
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
  Rb  Rb0  1  0.463  0.537  0.750  1.0
  Rb  Rb1  1  0.537  0.463  0.250  1.0
  Rb  Rb2  1  0.002  0.998  0.750  1.0
  Rb  Rb3  1  0.998  0.002  0.250  1.0
  Rb  Rb4  1  0.123  0.274  0.171  1.0
  Rb  Rb5  1  0.726  0.877  0.329  1.0
  Rb  Rb6  1  0.877  0.726  0.829  1.0
  Rb  Rb7  1  0.274  0.123  0.671  1.0
  As  As8  1  0.510  0.795  0.956  1.0
  As  As9  1  0.807  0.411  0.851  1.0
  As  As10  1  0.589  0.193  0.649  1.0
  As  As11  1  0.193  0.589  0.149  1.0
  As  As12  1  0.411  0.807  0.351  1.0
  As  As13  1  0.205  0.490  0.544  1.0
  As  As14  1  0.490  0.205  0.044  1.0
  As  As15  1  0.795  0.510  0.456  1.0
  Se  Se16  1  0.190  0.016  0.442  1.0
  Se  Se17  1  0.984  0.810  0.058  1.0
  Se  Se18  1  0.810  0.984  0.558  1.0
  Se  Se19  1  0.911  0.479  0.656  1.0
  Se  Se20  1  0.016  0.190  0.942  1.0
  Se  Se21  1  0.479  0.911  0.156  1.0
  Se  Se22  1  0.089  0.521  0.344  1.0
  Se  Se23  1  0.521  0.089  0.844  1.0
  Se  Se24  1  0.777  0.340  0.507  1.0
  Se  Se25  1  0.660  0.223  0.993  1.0
  Se  Se26  1  0.223  0.660  0.493  1.0
  Se  Se27  1  0.340  0.777  0.007  1.0
  Se  Se28  1  0.558  0.744  0.536  1.0
  Se  Se29  1  0.256  0.442  0.964  1.0
  Se  Se30  1  0.442  0.256  0.464  1.0
  Se  Se31  1  0.744  0.558  0.036  1.0
[/CIF]
.