The compound described by KBe2B3O7 crystallizes in the orthorhombic Pmn2_1 space group. There are two inequivalent K sites. In the first K site, K(1) is bonded in a 6-coordinate geometry to one O(1), one O(8), and four equivalent O(5) atoms. In the second K site, K(2) is bonded in a 5-coordinate geometry to one O(3), two equivalent O(7), and two equivalent O(9) atoms. There are two inequivalent Be sites. In the first Be site, Be(1) is bonded to one O(1), one O(5), and two equivalent O(2) atoms to form corner-sharing BeO4 tetrahedra. In the second Be site, Be(2) is bonded to one O(3), one O(9), and two equivalent O(4) atoms to form corner-sharing BeO4 tetrahedra. There are four inequivalent B sites. In the first B site, B(1) is bonded in a trigonal planar geometry to one O(1) and two equivalent O(2) atoms. In the second B site, B(2) is bonded in a trigonal planar geometry to one O(3) and two equivalent O(4) atoms. In the third B site, B(3) is bonded in a trigonal planar geometry to one O(5), one O(6), and one O(7) atom. In the fourth B site, B(4) is bonded in a trigonal planar geometry to one O(7), one O(8), and one O(9) atom. There are nine inequivalent O sites. In the first O site, O(4) is bonded in a trigonal planar geometry to two equivalent Be(2) and one B(2) atom. In the second O site, O(5) is bonded in a distorted bent 120 degrees geometry to two equivalent K(1), one Be(1), and one B(3) atom. In the third O site, O(6) is bonded in a bent 120 degrees geometry to two equivalent B(3) atoms. In the fourth O site, O(7) is bonded in a distorted bent 150 degrees geometry to one K(2), one B(3), and one B(4) atom. In the fifth O site, O(8) is bonded in a distorted bent 120 degrees geometry to one K(1) and two equivalent B(4) atoms. In the sixth O site, O(9) is bonded in a distorted bent 150 degrees geometry to one K(2), one Be(2), and one B(4) atom. In the seventh O site, O(1) is bonded in a trigonal planar geometry to one K(1), two equivalent Be(1), and one B(1) atom. In the eighth O site, O(2) is bonded in a trigonal planar geometry to two equivalent Be(1) and one B(1) atom. In the ninth O site, O(3) is bonded in a distorted trigonal planar geometry to one K(2), two equivalent Be(2), and one B(2) atom. is represented by the CIF file [CIF]
data_KBe2B3O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.417
_cell_length_b   7.721
_cell_length_c   17.699
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   603.585
_cell_formula_units_Z   4
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  0.106  0.000  0.363  1.0
  K  K1  1  0.606  0.500  0.637  1.0
  K  K2  1  0.177  0.500  0.147  1.0
  K  K3  1  0.677  0.000  0.853  1.0
  Be  Be4  1  0.626  0.312  0.458  1.0
  Be  Be5  1  0.626  0.688  0.458  1.0
  Be  Be6  1  0.126  0.188  0.542  1.0
  Be  Be7  1  0.126  0.812  0.542  1.0
  Be  Be8  1  0.771  0.176  0.037  1.0
  Be  Be9  1  0.771  0.824  0.037  1.0
  Be  Be10  1  0.271  0.324  0.963  1.0
  Be  Be11  1  0.271  0.676  0.963  1.0
  B  B12  1  0.124  0.500  0.480  1.0
  B  B13  1  0.624  0.000  0.520  1.0
  B  B14  1  0.266  0.000  0.009  1.0
  B  B15  1  0.766  0.500  0.991  1.0
  B  B16  1  0.545  0.340  0.315  1.0
  B  B17  1  0.545  0.660  0.315  1.0
  B  B18  1  0.045  0.160  0.685  1.0
  B  B19  1  0.045  0.840  0.685  1.0
  B  B20  1  0.671  0.165  0.193  1.0
  B  B21  1  0.671  0.835  0.193  1.0
  B  B22  1  0.171  0.335  0.807  1.0
  B  B23  1  0.171  0.665  0.807  1.0
  O  O24  1  0.812  0.500  0.473  1.0
  O  O25  1  0.312  0.000  0.527  1.0
  O  O26  1  0.275  0.343  0.487  1.0
  O  O27  1  0.275  0.657  0.487  1.0
  O  O28  1  0.775  0.157  0.513  1.0
  O  O29  1  0.775  0.843  0.513  1.0
  O  O30  1  0.954  0.000  0.010  1.0
  O  O31  1  0.454  0.500  0.990  1.0
  O  O32  1  0.420  0.155  0.007  1.0
  O  O33  1  0.420  0.845  0.007  1.0
  O  O34  1  0.920  0.345  0.993  1.0
  O  O35  1  0.920  0.655  0.993  1.0
  O  O36  1  0.637  0.239  0.373  1.0
  O  O37  1  0.637  0.761  0.373  1.0
  O  O38  1  0.137  0.261  0.627  1.0
  O  O39  1  0.137  0.739  0.627  1.0
  O  O40  1  0.408  0.500  0.331  1.0
  O  O41  1  0.908  0.000  0.669  1.0
  O  O42  1  0.573  0.302  0.239  1.0
  O  O43  1  0.573  0.698  0.239  1.0
  O  O44  1  0.073  0.198  0.761  1.0
  O  O45  1  0.073  0.802  0.761  1.0
  O  O46  1  0.632  0.000  0.224  1.0
  O  O47  1  0.132  0.500  0.776  1.0
  O  O48  1  0.784  0.206  0.125  1.0
  O  O49  1  0.784  0.794  0.125  1.0
  O  O50  1  0.284  0.294  0.875  1.0
  O  O51  1  0.284  0.706  0.875  1.0
[/CIF]
.
The compound described by KBe2B3O7 crystallizes in the orthorhombic Pmn2_1 space group. There are two inequivalent K sites. In the first K site, K(1) is bonded in a 6-coordinate geometry to one O(1), one O(8), and four equivalent O(5) atoms. In the second K site, K(2) is bonded in a 5-coordinate geometry to one O(3), two equivalent O(7), and two equivalent O(9) atoms. There are two inequivalent Be sites. In the first Be site, Be(1) is bonded to one O(1), one O(5), and two equivalent O(2) atoms to form corner-sharing BeO4 tetrahedra. In the second Be site, Be(2) is bonded to one O(3), one O(9), and two equivalent O(4) atoms to form corner-sharing BeO4 tetrahedra. There are four inequivalent B sites. In the first B site, B(1) is bonded in a trigonal planar geometry to one O(1) and two equivalent O(2) atoms. In the second B site, B(2) is bonded in a trigonal planar geometry to one O(3) and two equivalent O(4) atoms. In the third B site, B(3) is bonded in a trigonal planar geometry to one O(5), one O(6), and one O(7) atom. In the fourth B site, B(4) is bonded in a trigonal planar geometry to one O(7), one O(8), and one O(9) atom. There are nine inequivalent O sites. In the first O site, O(4) is bonded in a trigonal planar geometry to two equivalent Be(2) and one B(2) atom. In the second O site, O(5) is bonded in a distorted bent 120 degrees geometry to two equivalent K(1), one Be(1), and one B(3) atom. In the third O site, O(6) is bonded in a bent 120 degrees geometry to two equivalent B(3) atoms. In the fourth O site, O(7) is bonded in a distorted bent 150 degrees geometry to one K(2), one B(3), and one B(4) atom. In the fifth O site, O(8) is bonded in a distorted bent 120 degrees geometry to one K(1) and two equivalent B(4) atoms. In the sixth O site, O(9) is bonded in a distorted bent 150 degrees geometry to one K(2), one Be(2), and one B(4) atom. In the seventh O site, O(1) is bonded in a trigonal planar geometry to one K(1), two equivalent Be(1), and one B(1) atom. In the eighth O site, O(2) is bonded in a trigonal planar geometry to two equivalent Be(1) and one B(1) atom. In the ninth O site, O(3) is bonded in a distorted trigonal planar geometry to one K(2), two equivalent Be(2), and one B(2) atom. is represented by the CIF file [CIF]
data_KBe2B3O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.417
_cell_length_b   7.721
_cell_length_c   17.699
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   603.585
_cell_formula_units_Z   4
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  0.106  0.000  0.363  1.0
  K  K1  1  0.606  0.500  0.637  1.0
  K  K2  1  0.177  0.500  0.147  1.0
  K  K3  1  0.677  0.000  0.853  1.0
  Be  Be4  1  0.626  0.312  0.458  1.0
  Be  Be5  1  0.626  0.688  0.458  1.0
  Be  Be6  1  0.126  0.188  0.542  1.0
  Be  Be7  1  0.126  0.812  0.542  1.0
  Be  Be8  1  0.771  0.176  0.037  1.0
  Be  Be9  1  0.771  0.824  0.037  1.0
  Be  Be10  1  0.271  0.324  0.963  1.0
  Be  Be11  1  0.271  0.676  0.963  1.0
  B  B12  1  0.124  0.500  0.480  1.0
  B  B13  1  0.624  0.000  0.520  1.0
  B  B14  1  0.266  0.000  0.009  1.0
  B  B15  1  0.766  0.500  0.991  1.0
  B  B16  1  0.545  0.340  0.315  1.0
  B  B17  1  0.545  0.660  0.315  1.0
  B  B18  1  0.045  0.160  0.685  1.0
  B  B19  1  0.045  0.840  0.685  1.0
  B  B20  1  0.671  0.165  0.193  1.0
  B  B21  1  0.671  0.835  0.193  1.0
  B  B22  1  0.171  0.335  0.807  1.0
  B  B23  1  0.171  0.665  0.807  1.0
  O  O24  1  0.812  0.500  0.473  1.0
  O  O25  1  0.312  0.000  0.527  1.0
  O  O26  1  0.275  0.343  0.487  1.0
  O  O27  1  0.275  0.657  0.487  1.0
  O  O28  1  0.775  0.157  0.513  1.0
  O  O29  1  0.775  0.843  0.513  1.0
  O  O30  1  0.954  0.000  0.010  1.0
  O  O31  1  0.454  0.500  0.990  1.0
  O  O32  1  0.420  0.155  0.007  1.0
  O  O33  1  0.420  0.845  0.007  1.0
  O  O34  1  0.920  0.345  0.993  1.0
  O  O35  1  0.920  0.655  0.993  1.0
  O  O36  1  0.637  0.239  0.373  1.0
  O  O37  1  0.637  0.761  0.373  1.0
  O  O38  1  0.137  0.261  0.627  1.0
  O  O39  1  0.137  0.739  0.627  1.0
  O  O40  1  0.408  0.500  0.331  1.0
  O  O41  1  0.908  0.000  0.669  1.0
  O  O42  1  0.573  0.302  0.239  1.0
  O  O43  1  0.573  0.698  0.239  1.0
  O  O44  1  0.073  0.198  0.761  1.0
  O  O45  1  0.073  0.802  0.761  1.0
  O  O46  1  0.632  0.000  0.224  1.0
  O  O47  1  0.132  0.500  0.776  1.0
  O  O48  1  0.784  0.206  0.125  1.0
  O  O49  1  0.784  0.794  0.125  1.0
  O  O50  1  0.284  0.294  0.875  1.0
  O  O51  1  0.284  0.706  0.875  1.0
[/CIF]
.