The material described by KCu4(AsO4)3 is Esseneite-like structured and crystallizes in the monoclinic C2/c space group. K(1) is bonded to two equivalent O(5), two equivalent O(6), and four equivalent O(1) atoms to form distorted KO8 hexagonal bipyramids that share corners with two equivalent As(1)O4 tetrahedra, edges with two equivalent K(1)O8 hexagonal bipyramids, edges with four equivalent Cu(1)O6 octahedra,  an edgeedge with one As(2)O4 tetrahedra, and edges with two equivalent As(1)O4 tetrahedra. There are three inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to one O(1), one O(4), one O(5), one O(6), and two equivalent O(2) atoms to form distorted CuO6 octahedra that share corners with two equivalent As(2)O4 tetrahedra, corners with four equivalent As(1)O4 tetrahedra, edges with two equivalent K(1)O8 hexagonal bipyramids, and  an edgeedge with one Cu(1)O6 octahedra. In the second Cu site, Cu(2) is bonded in a square co-planar geometry to two equivalent O(3) and two equivalent O(4) atoms. In the third Cu site, Cu(3) is bonded in a 6-coordinate geometry to two equivalent O(3), two equivalent O(5), and two equivalent O(6) atoms. There are two inequivalent As sites. In the first As site, As(1) is bonded to one O(1), one O(2), one O(3), and one O(6) atom to form AsO4 tetrahedra that share  a cornercorner with one K(1)O8 hexagonal bipyramid, corners with four equivalent Cu(1)O6 octahedra, and  an edgeedge with one K(1)O8 hexagonal bipyramid. The corner-sharing octahedral tilt angles range from 39-60°. In the second As site, As(2) is bonded to two equivalent O(4) and two equivalent O(5) atoms to form AsO4 tetrahedra that share corners with four equivalent Cu(1)O6 octahedra and  an edgeedge with one K(1)O8 hexagonal bipyramid. The corner-sharing octahedral tilt angles range from 56-61°. There are six inequivalent O sites. In the first O site, O(1) is bonded to two equivalent K(1), one Cu(1), and one As(1) atom to form distorted OK2CuAs trigonal pyramids that share corners with two equivalent O(6)KCu2As trigonal pyramids, corners with four equivalent O(1)K2CuAs trigonal pyramids,  an edgeedge with one O(1)K2CuAs trigonal pyramid, and edges with two equivalent O(6)KCu2As trigonal pyramids. In the second O site, O(2) is bonded in a distorted bent 120 degrees geometry to two equivalent Cu(1) and one As(1) atom. In the third O site, O(3) is bonded in a trigonal planar geometry to one Cu(2), one Cu(3), and one As(1) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Cu(1), one Cu(2), and one As(2) atom. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to one K(1), one Cu(1), one Cu(3), and one As(2) atom. In the sixth O site, O(6) is bonded to one K(1), one Cu(1), one Cu(3), and one As(1) atom to form distorted OKCu2As trigonal pyramids that share corners with two equivalent O(1)K2CuAs trigonal pyramids,  an edgeedge with one O(6)KCu2As trigonal pyramid, and edges with two equivalent O(1)K2CuAs trigonal pyramids. is represented by the CIF card [CIF]
data_KCu4(AsO4)3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.842
_cell_length_b   8.842
_cell_length_c   7.550
_cell_angle_alpha   70.290
_cell_angle_beta   70.290
_cell_angle_gamma   90.679
_symmetry_Int_Tables_number   1
_cell_volume   517.848
_cell_formula_units_Z   2
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  0.012  0.988  0.750  1.0
  K  K1  1  0.988  0.012  0.250  1.0
  Cu  Cu2  1  0.618  0.932  0.644  1.0
  Cu  Cu3  1  0.505  0.495  0.250  1.0
  Cu  Cu4  1  0.737  0.263  0.750  1.0
  Cu  Cu5  1  0.932  0.618  0.144  1.0
  Cu  Cu6  1  0.263  0.737  0.250  1.0
  Cu  Cu7  1  0.495  0.505  0.750  1.0
  Cu  Cu8  1  0.068  0.382  0.856  1.0
  Cu  Cu9  1  0.382  0.068  0.356  1.0
  As  As10  1  0.352  0.113  0.876  1.0
  As  As11  1  0.113  0.352  0.376  1.0
  As  As12  1  0.887  0.648  0.624  1.0
  As  As13  1  0.724  0.276  0.250  1.0
  As  As14  1  0.276  0.724  0.750  1.0
  As  As15  1  0.648  0.887  0.124  1.0
  O  O16  1  0.174  0.186  0.867  1.0
  O  O17  1  0.826  0.814  0.133  1.0
  O  O18  1  0.584  0.972  0.307  1.0
  O  O19  1  0.972  0.584  0.807  1.0
  O  O20  1  0.499  0.726  0.180  1.0
  O  O21  1  0.481  0.723  0.741  1.0
  O  O22  1  0.726  0.499  0.680  1.0
  O  O23  1  0.501  0.274  0.820  1.0
  O  O24  1  0.155  0.749  0.966  1.0
  O  O25  1  0.186  0.174  0.367  1.0
  O  O26  1  0.519  0.277  0.259  1.0
  O  O27  1  0.686  0.021  0.880  1.0
  O  O28  1  0.979  0.314  0.620  1.0
  O  O29  1  0.021  0.686  0.380  1.0
  O  O30  1  0.845  0.251  0.034  1.0
  O  O31  1  0.274  0.501  0.320  1.0
  O  O32  1  0.749  0.155  0.466  1.0
  O  O33  1  0.277  0.519  0.759  1.0
  O  O34  1  0.416  0.028  0.693  1.0
  O  O35  1  0.314  0.979  0.120  1.0
  O  O36  1  0.028  0.416  0.193  1.0
  O  O37  1  0.251  0.845  0.534  1.0
  O  O38  1  0.723  0.481  0.241  1.0
  O  O39  1  0.814  0.826  0.633  1.0
[/CIF]
.
The material described by KCu4(AsO4)3 is Esseneite-like structured and crystallizes in the monoclinic C2/c space group. K(1) is bonded to two equivalent O(5), two equivalent O(6), and four equivalent O(1) atoms to form distorted KO8 hexagonal bipyramids that share corners with two equivalent As(1)O4 tetrahedra, edges with two equivalent K(1)O8 hexagonal bipyramids, edges with four equivalent Cu(1)O6 octahedra,  an edgeedge with one As(2)O4 tetrahedra, and edges with two equivalent As(1)O4 tetrahedra. There are three inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to one O(1), one O(4), one O(5), one O(6), and two equivalent O(2) atoms to form distorted CuO6 octahedra that share corners with two equivalent As(2)O4 tetrahedra, corners with four equivalent As(1)O4 tetrahedra, edges with two equivalent K(1)O8 hexagonal bipyramids, and  an edgeedge with one Cu(1)O6 octahedra. In the second Cu site, Cu(2) is bonded in a square co-planar geometry to two equivalent O(3) and two equivalent O(4) atoms. In the third Cu site, Cu(3) is bonded in a 6-coordinate geometry to two equivalent O(3), two equivalent O(5), and two equivalent O(6) atoms. There are two inequivalent As sites. In the first As site, As(1) is bonded to one O(1), one O(2), one O(3), and one O(6) atom to form AsO4 tetrahedra that share  a cornercorner with one K(1)O8 hexagonal bipyramid, corners with four equivalent Cu(1)O6 octahedra, and  an edgeedge with one K(1)O8 hexagonal bipyramid. The corner-sharing octahedral tilt angles range from 39-60°. In the second As site, As(2) is bonded to two equivalent O(4) and two equivalent O(5) atoms to form AsO4 tetrahedra that share corners with four equivalent Cu(1)O6 octahedra and  an edgeedge with one K(1)O8 hexagonal bipyramid. The corner-sharing octahedral tilt angles range from 56-61°. There are six inequivalent O sites. In the first O site, O(1) is bonded to two equivalent K(1), one Cu(1), and one As(1) atom to form distorted OK2CuAs trigonal pyramids that share corners with two equivalent O(6)KCu2As trigonal pyramids, corners with four equivalent O(1)K2CuAs trigonal pyramids,  an edgeedge with one O(1)K2CuAs trigonal pyramid, and edges with two equivalent O(6)KCu2As trigonal pyramids. In the second O site, O(2) is bonded in a distorted bent 120 degrees geometry to two equivalent Cu(1) and one As(1) atom. In the third O site, O(3) is bonded in a trigonal planar geometry to one Cu(2), one Cu(3), and one As(1) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Cu(1), one Cu(2), and one As(2) atom. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to one K(1), one Cu(1), one Cu(3), and one As(2) atom. In the sixth O site, O(6) is bonded to one K(1), one Cu(1), one Cu(3), and one As(1) atom to form distorted OKCu2As trigonal pyramids that share corners with two equivalent O(1)K2CuAs trigonal pyramids,  an edgeedge with one O(6)KCu2As trigonal pyramid, and edges with two equivalent O(1)K2CuAs trigonal pyramids. is represented by the CIF card [CIF]
data_KCu4(AsO4)3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.842
_cell_length_b   8.842
_cell_length_c   7.550
_cell_angle_alpha   70.290
_cell_angle_beta   70.290
_cell_angle_gamma   90.679
_symmetry_Int_Tables_number   1
_cell_volume   517.848
_cell_formula_units_Z   2
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  0.012  0.988  0.750  1.0
  K  K1  1  0.988  0.012  0.250  1.0
  Cu  Cu2  1  0.618  0.932  0.644  1.0
  Cu  Cu3  1  0.505  0.495  0.250  1.0
  Cu  Cu4  1  0.737  0.263  0.750  1.0
  Cu  Cu5  1  0.932  0.618  0.144  1.0
  Cu  Cu6  1  0.263  0.737  0.250  1.0
  Cu  Cu7  1  0.495  0.505  0.750  1.0
  Cu  Cu8  1  0.068  0.382  0.856  1.0
  Cu  Cu9  1  0.382  0.068  0.356  1.0
  As  As10  1  0.352  0.113  0.876  1.0
  As  As11  1  0.113  0.352  0.376  1.0
  As  As12  1  0.887  0.648  0.624  1.0
  As  As13  1  0.724  0.276  0.250  1.0
  As  As14  1  0.276  0.724  0.750  1.0
  As  As15  1  0.648  0.887  0.124  1.0
  O  O16  1  0.174  0.186  0.867  1.0
  O  O17  1  0.826  0.814  0.133  1.0
  O  O18  1  0.584  0.972  0.307  1.0
  O  O19  1  0.972  0.584  0.807  1.0
  O  O20  1  0.499  0.726  0.180  1.0
  O  O21  1  0.481  0.723  0.741  1.0
  O  O22  1  0.726  0.499  0.680  1.0
  O  O23  1  0.501  0.274  0.820  1.0
  O  O24  1  0.155  0.749  0.966  1.0
  O  O25  1  0.186  0.174  0.367  1.0
  O  O26  1  0.519  0.277  0.259  1.0
  O  O27  1  0.686  0.021  0.880  1.0
  O  O28  1  0.979  0.314  0.620  1.0
  O  O29  1  0.021  0.686  0.380  1.0
  O  O30  1  0.845  0.251  0.034  1.0
  O  O31  1  0.274  0.501  0.320  1.0
  O  O32  1  0.749  0.155  0.466  1.0
  O  O33  1  0.277  0.519  0.759  1.0
  O  O34  1  0.416  0.028  0.693  1.0
  O  O35  1  0.314  0.979  0.120  1.0
  O  O36  1  0.028  0.416  0.193  1.0
  O  O37  1  0.251  0.845  0.534  1.0
  O  O38  1  0.723  0.481  0.241  1.0
  O  O39  1  0.814  0.826  0.633  1.0
[/CIF]
.