The material described by RbK2MgTbV2O8 crystallizes in the monoclinic Cm space group. Rb(1) is bonded in a 8-coordinate geometry to one Mg(1), one O(1), one O(4), one O(5), two equivalent O(2), and two equivalent O(6) atoms. There are two inequivalent K sites. In the first K site, K(1) is bonded in a 7-coordinate geometry to one O(6), two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms. In the second K site, K(2) is bonded in a 7-coordinate geometry to one O(5), two equivalent O(1), and four equivalent O(2) atoms. Mg(1) is bonded in a distorted trigonal planar geometry to one Rb(1), one O(6), and two equivalent O(3) atoms. Tb(1) is bonded to one O(1), one O(4), two equivalent O(2), and two equivalent O(3) atoms to form TbO6 octahedra that share corners with three equivalent V(1)O4 tetrahedra and corners with three equivalent V(2)O4 tetrahedra. There are two inequivalent V sites. In the first V site, V(1) is bonded to one O(1), one O(6), and two equivalent O(2) atoms to form VO4 tetrahedra that share corners with three equivalent Tb(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 9-15°. In the second V site, V(2) is bonded to one O(4), one O(5), and two equivalent O(3) atoms to form VO4 tetrahedra that share corners with three equivalent Tb(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 17-24°. There are six inequivalent O sites. In the first O site, O(1) is bonded in a 5-coordinate geometry to one Rb(1), two equivalent K(2), one Tb(1), and one V(1) atom. In the second O site, O(2) is bonded in a 6-coordinate geometry to one Rb(1), one K(1), two equivalent K(2), one Tb(1), and one V(1) atom. In the third O site, O(3) is bonded in a 4-coordinate geometry to one K(1), one Mg(1), one Tb(1), and one V(2) atom. In the fourth O site, O(4) is bonded in a 2-coordinate geometry to one Rb(1), two equivalent K(1), one Tb(1), and one V(2) atom. In the fifth O site, O(5) is bonded in a distorted T-shaped geometry to one Rb(1), one K(2), and one V(2) atom. In the sixth O site, O(6) is bonded in a distorted bent 120 degrees geometry to two equivalent Rb(1), one K(1), one Mg(1), and one V(1) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_K2RbTbMgV2O8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.198
_cell_length_b   6.198
_cell_length_c   7.879
_cell_angle_alpha   84.690
_cell_angle_beta   95.310
_cell_angle_gamma   121.364
_symmetry_Int_Tables_number   1
_cell_volume   257.031
_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
  K  K0  1  0.605  0.395  0.850  1.0
  K  K1  1  0.347  0.653  0.191  1.0
  Rb  Rb2  1  0.060  0.940  0.453  1.0
  Tb  Tb3  1  0.004  0.996  0.011  1.0
  Mg  Mg4  1  0.829  0.171  0.658  1.0
  V  V5  1  0.691  0.309  0.264  1.0
  V  V6  1  0.306  0.694  0.737  1.0
  O  O7  1  0.841  0.159  0.184  1.0
  O  O8  1  0.836  0.634  0.166  1.0
  O  O9  1  0.366  0.164  0.166  1.0
  O  O10  1  0.654  0.873  0.812  1.0
  O  O11  1  0.127  0.346  0.812  1.0
  O  O12  1  0.157  0.843  0.824  1.0
  O  O13  1  0.314  0.686  0.519  1.0
  O  O14  1  0.686  0.314  0.495  1.0
[/CIF]
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The material described by RbK2MgTbV2O8 crystallizes in the monoclinic Cm space group. Rb(1) is bonded in a 8-coordinate geometry to one Mg(1), one O(1), one O(4), one O(5), two equivalent O(2), and two equivalent O(6) atoms. There are two inequivalent K sites. In the first K site, K(1) is bonded in a 7-coordinate geometry to one O(6), two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms. In the second K site, K(2) is bonded in a 7-coordinate geometry to one O(5), two equivalent O(1), and four equivalent O(2) atoms. Mg(1) is bonded in a distorted trigonal planar geometry to one Rb(1), one O(6), and two equivalent O(3) atoms. Tb(1) is bonded to one O(1), one O(4), two equivalent O(2), and two equivalent O(3) atoms to form TbO6 octahedra that share corners with three equivalent V(1)O4 tetrahedra and corners with three equivalent V(2)O4 tetrahedra. There are two inequivalent V sites. In the first V site, V(1) is bonded to one O(1), one O(6), and two equivalent O(2) atoms to form VO4 tetrahedra that share corners with three equivalent Tb(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 9-15°. In the second V site, V(2) is bonded to one O(4), one O(5), and two equivalent O(3) atoms to form VO4 tetrahedra that share corners with three equivalent Tb(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 17-24°. There are six inequivalent O sites. In the first O site, O(1) is bonded in a 5-coordinate geometry to one Rb(1), two equivalent K(2), one Tb(1), and one V(1) atom. In the second O site, O(2) is bonded in a 6-coordinate geometry to one Rb(1), one K(1), two equivalent K(2), one Tb(1), and one V(1) atom. In the third O site, O(3) is bonded in a 4-coordinate geometry to one K(1), one Mg(1), one Tb(1), and one V(2) atom. In the fourth O site, O(4) is bonded in a 2-coordinate geometry to one Rb(1), two equivalent K(1), one Tb(1), and one V(2) atom. In the fifth O site, O(5) is bonded in a distorted T-shaped geometry to one Rb(1), one K(2), and one V(2) atom. In the sixth O site, O(6) is bonded in a distorted bent 120 degrees geometry to two equivalent Rb(1), one K(1), one Mg(1), and one V(1) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_K2RbTbMgV2O8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.198
_cell_length_b   6.198
_cell_length_c   7.879
_cell_angle_alpha   84.690
_cell_angle_beta   95.310
_cell_angle_gamma   121.364
_symmetry_Int_Tables_number   1
_cell_volume   257.031
_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
  K  K0  1  0.605  0.395  0.850  1.0
  K  K1  1  0.347  0.653  0.191  1.0
  Rb  Rb2  1  0.060  0.940  0.453  1.0
  Tb  Tb3  1  0.004  0.996  0.011  1.0
  Mg  Mg4  1  0.829  0.171  0.658  1.0
  V  V5  1  0.691  0.309  0.264  1.0
  V  V6  1  0.306  0.694  0.737  1.0
  O  O7  1  0.841  0.159  0.184  1.0
  O  O8  1  0.836  0.634  0.166  1.0
  O  O9  1  0.366  0.164  0.166  1.0
  O  O10  1  0.654  0.873  0.812  1.0
  O  O11  1  0.127  0.346  0.812  1.0
  O  O12  1  0.157  0.843  0.824  1.0
  O  O13  1  0.314  0.686  0.519  1.0
  O  O14  1  0.686  0.314  0.495  1.0
[/CIF]
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