The compound described by Ba4Sc2Cu2O9 crystallizes in the orthorhombic Fmmm space group. Ba(1) is bonded in a 9-coordinate geometry to one O(4), two equivalent O(2), two equivalent O(3), and four equivalent O(1) atoms. Sc(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form corner-sharing ScO6 octahedra. The corner-sharing octahedral tilt angles range from 0-5°. Cu(1) is bonded in a T-shaped geometry to one O(4) and two equivalent O(1) atoms. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 6-coordinate geometry to four equivalent Ba(1), one Sc(1), and one Cu(1) atom. In the second O site, O(2) is bonded to four equivalent Ba(1) and two equivalent Sc(1) atoms to form distorted OBa4Sc2 octahedra that share corners with two equivalent O(4)Ba4Cu2 octahedra, corners with two equivalent O(2)Ba4Sc2 octahedra,  an edgeedge with one O(4)Ba4Cu2 octahedra, edges with two equivalent O(2)Ba4Sc2 octahedra, and faces with four equivalent O(3)Ba4Sc2 octahedra. The corner-sharing octahedral tilt angles range from 0-3°. In the third O site, O(3) is bonded to four equivalent Ba(1) and two equivalent Sc(1) atoms to form distorted OBa4Sc2 octahedra that share corners with two equivalent O(3)Ba4Sc2 octahedra, corners with four equivalent O(4)Ba4Cu2 octahedra, edges with two equivalent O(3)Ba4Sc2 octahedra, and faces with four equivalent O(2)Ba4Sc2 octahedra. The corner-sharing octahedral tilt angles range from 0-61°. In the fourth O site, O(4) is bonded to four equivalent Ba(1) and two equivalent Cu(1) atoms to form a mixture of distorted corner and edge-sharing OBa4Cu2 octahedra. The corner-sharing octahedral tilt angles range from 3-61°. is represented by the Crystallographic Information File (CIF) [CIF]
data_Ba4Sc2Cu2O9
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.983
_cell_length_b   8.967
_cell_length_c   5.884
_cell_angle_alpha   71.014
_cell_angle_beta   70.718
_cell_angle_gamma   38.268
_symmetry_Int_Tables_number   1
_cell_volume   275.287
_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
  Ba  Ba0  1  0.878  0.386  0.122  1.0
  Ba  Ba1  1  0.386  0.878  0.614  1.0
  Ba  Ba2  1  0.614  0.122  0.386  1.0
  Ba  Ba3  1  0.122  0.614  0.878  1.0
  Sc  Sc4  1  0.500  0.000  0.000  1.0
  Sc  Sc5  1  0.000  0.500  0.500  1.0
  Cu  Cu6  1  0.727  0.273  0.727  1.0
  Cu  Cu7  1  0.273  0.727  0.273  1.0
  O  O8  1  0.880  0.343  0.657  1.0
  O  O9  1  0.343  0.880  0.120  1.0
  O  O10  1  0.657  0.120  0.880  1.0
  O  O11  1  0.120  0.657  0.343  1.0
  O  O12  1  0.744  0.744  0.256  1.0
  O  O13  1  0.256  0.256  0.744  1.0
  O  O14  1  0.250  0.250  0.250  1.0
  O  O15  1  0.750  0.750  0.750  1.0
  O  O16  1  0.500  0.500  0.500  1.0
[/CIF]
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The compound described by Ba4Sc2Cu2O9 crystallizes in the orthorhombic Fmmm space group. Ba(1) is bonded in a 9-coordinate geometry to one O(4), two equivalent O(2), two equivalent O(3), and four equivalent O(1) atoms. Sc(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form corner-sharing ScO6 octahedra. The corner-sharing octahedral tilt angles range from 0-5°. Cu(1) is bonded in a T-shaped geometry to one O(4) and two equivalent O(1) atoms. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 6-coordinate geometry to four equivalent Ba(1), one Sc(1), and one Cu(1) atom. In the second O site, O(2) is bonded to four equivalent Ba(1) and two equivalent Sc(1) atoms to form distorted OBa4Sc2 octahedra that share corners with two equivalent O(4)Ba4Cu2 octahedra, corners with two equivalent O(2)Ba4Sc2 octahedra,  an edgeedge with one O(4)Ba4Cu2 octahedra, edges with two equivalent O(2)Ba4Sc2 octahedra, and faces with four equivalent O(3)Ba4Sc2 octahedra. The corner-sharing octahedral tilt angles range from 0-3°. In the third O site, O(3) is bonded to four equivalent Ba(1) and two equivalent Sc(1) atoms to form distorted OBa4Sc2 octahedra that share corners with two equivalent O(3)Ba4Sc2 octahedra, corners with four equivalent O(4)Ba4Cu2 octahedra, edges with two equivalent O(3)Ba4Sc2 octahedra, and faces with four equivalent O(2)Ba4Sc2 octahedra. The corner-sharing octahedral tilt angles range from 0-61°. In the fourth O site, O(4) is bonded to four equivalent Ba(1) and two equivalent Cu(1) atoms to form a mixture of distorted corner and edge-sharing OBa4Cu2 octahedra. The corner-sharing octahedral tilt angles range from 3-61°. is represented by the Crystallographic Information File (CIF) [CIF]
data_Ba4Sc2Cu2O9
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.983
_cell_length_b   8.967
_cell_length_c   5.884
_cell_angle_alpha   71.014
_cell_angle_beta   70.718
_cell_angle_gamma   38.268
_symmetry_Int_Tables_number   1
_cell_volume   275.287
_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
  Ba  Ba0  1  0.878  0.386  0.122  1.0
  Ba  Ba1  1  0.386  0.878  0.614  1.0
  Ba  Ba2  1  0.614  0.122  0.386  1.0
  Ba  Ba3  1  0.122  0.614  0.878  1.0
  Sc  Sc4  1  0.500  0.000  0.000  1.0
  Sc  Sc5  1  0.000  0.500  0.500  1.0
  Cu  Cu6  1  0.727  0.273  0.727  1.0
  Cu  Cu7  1  0.273  0.727  0.273  1.0
  O  O8  1  0.880  0.343  0.657  1.0
  O  O9  1  0.343  0.880  0.120  1.0
  O  O10  1  0.657  0.120  0.880  1.0
  O  O11  1  0.120  0.657  0.343  1.0
  O  O12  1  0.744  0.744  0.256  1.0
  O  O13  1  0.256  0.256  0.744  1.0
  O  O14  1  0.250  0.250  0.250  1.0
  O  O15  1  0.750  0.750  0.750  1.0
  O  O16  1  0.500  0.500  0.500  1.0
[/CIF]
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