The structure described by Er3GaO6 crystallizes in the orthorhombic Cmc2_1 space group. There are two inequivalent Er sites. In the first Er site, Er(1) is bonded to one O(1), two equivalent O(4), and four equivalent O(3) atoms to form distorted ErO7 pentagonal bipyramids that share  a cornercorner with one Ga(1)O4 tetrahedra, edges with two equivalent Er(1)O7 pentagonal bipyramids, and  an edgeedge with one Ga(1)O4 tetrahedra. In the second Er site, Er(2) is bonded in a 7-coordinate geometry to one O(1), two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms. Ga(1) is bonded to one O(1), one O(2), and two equivalent O(4) atoms to form distorted GaO4 tetrahedra that share  a cornercorner with one Er(1)O7 pentagonal bipyramid and  an edgeedge with one Er(1)O7 pentagonal bipyramid. There are four inequivalent O sites. In the first O site, O(1) is bonded to one Er(1), two equivalent Er(2), and one Ga(1) atom to form distorted OEr3Ga tetrahedra that share corners with eight equivalent O(3)Er4 tetrahedra,  a cornercorner with one O(2)Er4Ga trigonal bipyramid, corners with four equivalent O(4)Er3Ga trigonal pyramids, edges with two equivalent O(2)Er4Ga trigonal bipyramids, and edges with two equivalent O(4)Er3Ga trigonal pyramids. In the second O site, O(2) is bonded to four equivalent Er(2) and one Ga(1) atom to form distorted OEr4Ga trigonal bipyramids that share  a cornercorner with one O(1)Er3Ga tetrahedra, corners with four equivalent O(3)Er4 tetrahedra, corners with six equivalent O(4)Er3Ga trigonal pyramids, edges with two equivalent O(1)Er3Ga tetrahedra, edges with two equivalent O(3)Er4 tetrahedra, edges with two equivalent O(2)Er4Ga trigonal bipyramids, and edges with two equivalent O(4)Er3Ga trigonal pyramids. In the third O site, O(3) is bonded to two equivalent Er(1) and two equivalent Er(2) atoms to form OEr4 tetrahedra that share corners with two equivalent O(3)Er4 tetrahedra, corners with four equivalent O(1)Er3Ga tetrahedra, corners with two equivalent O(2)Er4Ga trigonal bipyramids, corners with six equivalent O(4)Er3Ga trigonal pyramids, edges with three equivalent O(3)Er4 tetrahedra,  an edgeedge with one O(2)Er4Ga trigonal bipyramid, and  an edgeedge with one O(4)Er3Ga trigonal pyramid. In the fourth O site, O(4) is bonded to one Er(1), two equivalent Er(2), and one Ga(1) atom to form distorted OEr3Ga trigonal pyramids that share corners with two equivalent O(1)Er3Ga tetrahedra, corners with six equivalent O(3)Er4 tetrahedra, corners with three equivalent O(2)Er4Ga trigonal bipyramids, corners with two equivalent O(4)Er3Ga trigonal pyramids,  an edgeedge with one O(1)Er3Ga tetrahedra,  an edgeedge with one O(3)Er4 tetrahedra,  an edgeedge with one O(2)Er4Ga trigonal bipyramid, and  an edgeedge with one O(4)Er3Ga trigonal pyramid. is represented by the CIF file [CIF]
data_Er3GaO6
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.999
_cell_length_b   6.999
_cell_length_c   5.350
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   102.833
_symmetry_Int_Tables_number   1
_cell_volume   255.545
_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
  Er  Er0  1  0.398  0.602  0.070  1.0
  Er  Er1  1  0.602  0.398  0.570  1.0
  Er  Er2  1  0.912  0.702  0.021  1.0
  Er  Er3  1  0.088  0.298  0.521  1.0
  Er  Er4  1  0.298  0.088  0.021  1.0
  Er  Er5  1  0.702  0.912  0.521  1.0
  Ga  Ga6  1  0.193  0.807  0.492  1.0
  Ga  Ga7  1  0.807  0.193  0.992  1.0
  O  O8  1  0.216  0.784  0.832  1.0
  O  O9  1  0.784  0.216  0.332  1.0
  O  O10  1  0.038  0.962  0.345  1.0
  O  O11  1  0.962  0.038  0.845  1.0
  O  O12  1  0.678  0.643  0.295  1.0
  O  O13  1  0.322  0.357  0.795  1.0
  O  O14  1  0.357  0.322  0.295  1.0
  O  O15  1  0.643  0.678  0.795  1.0
  O  O16  1  0.576  0.105  0.810  1.0
  O  O17  1  0.424  0.895  0.310  1.0
  O  O18  1  0.895  0.424  0.810  1.0
  O  O19  1  0.105  0.576  0.310  1.0
[/CIF]
.
The structure described by Er3GaO6 crystallizes in the orthorhombic Cmc2_1 space group. There are two inequivalent Er sites. In the first Er site, Er(1) is bonded to one O(1), two equivalent O(4), and four equivalent O(3) atoms to form distorted ErO7 pentagonal bipyramids that share  a cornercorner with one Ga(1)O4 tetrahedra, edges with two equivalent Er(1)O7 pentagonal bipyramids, and  an edgeedge with one Ga(1)O4 tetrahedra. In the second Er site, Er(2) is bonded in a 7-coordinate geometry to one O(1), two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms. Ga(1) is bonded to one O(1), one O(2), and two equivalent O(4) atoms to form distorted GaO4 tetrahedra that share  a cornercorner with one Er(1)O7 pentagonal bipyramid and  an edgeedge with one Er(1)O7 pentagonal bipyramid. There are four inequivalent O sites. In the first O site, O(1) is bonded to one Er(1), two equivalent Er(2), and one Ga(1) atom to form distorted OEr3Ga tetrahedra that share corners with eight equivalent O(3)Er4 tetrahedra,  a cornercorner with one O(2)Er4Ga trigonal bipyramid, corners with four equivalent O(4)Er3Ga trigonal pyramids, edges with two equivalent O(2)Er4Ga trigonal bipyramids, and edges with two equivalent O(4)Er3Ga trigonal pyramids. In the second O site, O(2) is bonded to four equivalent Er(2) and one Ga(1) atom to form distorted OEr4Ga trigonal bipyramids that share  a cornercorner with one O(1)Er3Ga tetrahedra, corners with four equivalent O(3)Er4 tetrahedra, corners with six equivalent O(4)Er3Ga trigonal pyramids, edges with two equivalent O(1)Er3Ga tetrahedra, edges with two equivalent O(3)Er4 tetrahedra, edges with two equivalent O(2)Er4Ga trigonal bipyramids, and edges with two equivalent O(4)Er3Ga trigonal pyramids. In the third O site, O(3) is bonded to two equivalent Er(1) and two equivalent Er(2) atoms to form OEr4 tetrahedra that share corners with two equivalent O(3)Er4 tetrahedra, corners with four equivalent O(1)Er3Ga tetrahedra, corners with two equivalent O(2)Er4Ga trigonal bipyramids, corners with six equivalent O(4)Er3Ga trigonal pyramids, edges with three equivalent O(3)Er4 tetrahedra,  an edgeedge with one O(2)Er4Ga trigonal bipyramid, and  an edgeedge with one O(4)Er3Ga trigonal pyramid. In the fourth O site, O(4) is bonded to one Er(1), two equivalent Er(2), and one Ga(1) atom to form distorted OEr3Ga trigonal pyramids that share corners with two equivalent O(1)Er3Ga tetrahedra, corners with six equivalent O(3)Er4 tetrahedra, corners with three equivalent O(2)Er4Ga trigonal bipyramids, corners with two equivalent O(4)Er3Ga trigonal pyramids,  an edgeedge with one O(1)Er3Ga tetrahedra,  an edgeedge with one O(3)Er4 tetrahedra,  an edgeedge with one O(2)Er4Ga trigonal bipyramid, and  an edgeedge with one O(4)Er3Ga trigonal pyramid. is represented by the CIF file [CIF]
data_Er3GaO6
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.999
_cell_length_b   6.999
_cell_length_c   5.350
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   102.833
_symmetry_Int_Tables_number   1
_cell_volume   255.545
_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
  Er  Er0  1  0.398  0.602  0.070  1.0
  Er  Er1  1  0.602  0.398  0.570  1.0
  Er  Er2  1  0.912  0.702  0.021  1.0
  Er  Er3  1  0.088  0.298  0.521  1.0
  Er  Er4  1  0.298  0.088  0.021  1.0
  Er  Er5  1  0.702  0.912  0.521  1.0
  Ga  Ga6  1  0.193  0.807  0.492  1.0
  Ga  Ga7  1  0.807  0.193  0.992  1.0
  O  O8  1  0.216  0.784  0.832  1.0
  O  O9  1  0.784  0.216  0.332  1.0
  O  O10  1  0.038  0.962  0.345  1.0
  O  O11  1  0.962  0.038  0.845  1.0
  O  O12  1  0.678  0.643  0.295  1.0
  O  O13  1  0.322  0.357  0.795  1.0
  O  O14  1  0.357  0.322  0.295  1.0
  O  O15  1  0.643  0.678  0.795  1.0
  O  O16  1  0.576  0.105  0.810  1.0
  O  O17  1  0.424  0.895  0.310  1.0
  O  O18  1  0.895  0.424  0.810  1.0
  O  O19  1  0.105  0.576  0.310  1.0
[/CIF]
.