The structure described by K2BSi5O12 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 5-coordinate geometry to one O(2), two equivalent O(4), and two equivalent O(7) atoms. In the second K site, K(2) is bonded in a 7-coordinate geometry to one O(3), two equivalent O(6), and four equivalent O(1) atoms. B(1) is bonded to one O(2), one O(3), and two equivalent O(7) atoms to form BO4 tetrahedra that share corners with two equivalent Si(2)O4 tetrahedra and corners with two equivalent Si(3)O4 tetrahedra. There are three inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(1), one O(4), one O(5), and one O(6) atom to form corner-sharing SiO4 tetrahedra. In the second Si site, Si(2) is bonded to one O(4), one O(5), one O(6), and one O(7) atom to form SiO4 tetrahedra that share  a cornercorner with one B(1)O4 tetrahedra and corners with three equivalent Si(1)O4 tetrahedra. In the third Si site, Si(3) is bonded to one O(2), one O(3), and two equivalent O(1) atoms to form SiO4 tetrahedra that share corners with two equivalent B(1)O4 tetrahedra and corners with two equivalent Si(1)O4 tetrahedra. There are seven inequivalent O sites. In the first O site, O(6) is bonded in a distorted bent 150 degrees geometry to one K(2), one Si(1), and one Si(2) atom. In the second O site, O(7) is bonded in a distorted bent 120 degrees geometry to one K(1), one B(1), and one Si(2) atom. In the third O site, O(1) is bonded in a distorted bent 150 degrees geometry to two equivalent K(2), one Si(1), and one Si(3) atom. In the fourth O site, O(2) is bonded in a 3-coordinate geometry to one K(1), one B(1), and one Si(3) atom. In the fifth O site, O(3) is bonded in a 2-coordinate geometry to one K(2), one B(1), and one Si(3) atom. In the sixth O site, O(4) is bonded in a distorted bent 150 degrees geometry to one K(1), one Si(1), and one Si(2) atom. In the seventh O site, O(5) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(2) atom. is represented by the CIF file [CIF]
data_K2Si5BO12
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.782
_cell_length_b   13.392
_cell_length_c   9.199
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   589.043
_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  0.947  0.000  0.942  1.0
  K  K1  1  0.053  0.500  0.442  1.0
  K  K2  1  0.466  0.000  0.269  1.0
  K  K3  1  0.534  0.500  0.769  1.0
  Si  Si4  1  0.856  0.710  0.945  1.0
  Si  Si5  1  0.144  0.790  0.445  1.0
  Si  Si6  1  0.144  0.210  0.445  1.0
  Si  Si7  1  0.856  0.290  0.945  1.0
  Si  Si8  1  0.358  0.799  0.777  1.0
  Si  Si9  1  0.642  0.701  0.277  1.0
  Si  Si10  1  0.642  0.299  0.277  1.0
  Si  Si11  1  0.358  0.201  0.777  1.0
  Si  Si12  1  0.938  0.000  0.531  1.0
  Si  Si13  1  0.062  0.500  0.031  1.0
  B  B14  1  0.437  0.000  0.701  1.0
  B  B15  1  0.563  0.500  0.201  1.0
  O  O16  1  0.986  0.597  0.927  1.0
  O  O17  1  0.014  0.903  0.427  1.0
  O  O18  1  0.014  0.097  0.427  1.0
  O  O19  1  0.986  0.403  0.927  1.0
  O  O20  1  0.134  0.000  0.672  1.0
  O  O21  1  0.866  0.500  0.172  1.0
  O  O22  1  0.605  0.000  0.565  1.0
  O  O23  1  0.395  0.500  0.065  1.0
  O  O24  1  0.908  0.708  0.393  1.0
  O  O25  1  0.092  0.792  0.893  1.0
  O  O26  1  0.092  0.208  0.893  1.0
  O  O27  1  0.908  0.292  0.393  1.0
  O  O28  1  0.248  0.769  0.612  1.0
  O  O29  1  0.752  0.731  0.112  1.0
  O  O30  1  0.752  0.269  0.112  1.0
  O  O31  1  0.248  0.231  0.612  1.0
  O  O32  1  0.591  0.716  0.831  1.0
  O  O33  1  0.409  0.784  0.331  1.0
  O  O34  1  0.409  0.216  0.331  1.0
  O  O35  1  0.591  0.284  0.831  1.0
  O  O36  1  0.500  0.909  0.788  1.0
  O  O37  1  0.500  0.591  0.288  1.0
  O  O38  1  0.500  0.409  0.288  1.0
  O  O39  1  0.500  0.091  0.788  1.0
[/CIF]
.
The structure described by K2BSi5O12 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 5-coordinate geometry to one O(2), two equivalent O(4), and two equivalent O(7) atoms. In the second K site, K(2) is bonded in a 7-coordinate geometry to one O(3), two equivalent O(6), and four equivalent O(1) atoms. B(1) is bonded to one O(2), one O(3), and two equivalent O(7) atoms to form BO4 tetrahedra that share corners with two equivalent Si(2)O4 tetrahedra and corners with two equivalent Si(3)O4 tetrahedra. There are three inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(1), one O(4), one O(5), and one O(6) atom to form corner-sharing SiO4 tetrahedra. In the second Si site, Si(2) is bonded to one O(4), one O(5), one O(6), and one O(7) atom to form SiO4 tetrahedra that share  a cornercorner with one B(1)O4 tetrahedra and corners with three equivalent Si(1)O4 tetrahedra. In the third Si site, Si(3) is bonded to one O(2), one O(3), and two equivalent O(1) atoms to form SiO4 tetrahedra that share corners with two equivalent B(1)O4 tetrahedra and corners with two equivalent Si(1)O4 tetrahedra. There are seven inequivalent O sites. In the first O site, O(6) is bonded in a distorted bent 150 degrees geometry to one K(2), one Si(1), and one Si(2) atom. In the second O site, O(7) is bonded in a distorted bent 120 degrees geometry to one K(1), one B(1), and one Si(2) atom. In the third O site, O(1) is bonded in a distorted bent 150 degrees geometry to two equivalent K(2), one Si(1), and one Si(3) atom. In the fourth O site, O(2) is bonded in a 3-coordinate geometry to one K(1), one B(1), and one Si(3) atom. In the fifth O site, O(3) is bonded in a 2-coordinate geometry to one K(2), one B(1), and one Si(3) atom. In the sixth O site, O(4) is bonded in a distorted bent 150 degrees geometry to one K(1), one Si(1), and one Si(2) atom. In the seventh O site, O(5) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(2) atom. is represented by the CIF file [CIF]
data_K2Si5BO12
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.782
_cell_length_b   13.392
_cell_length_c   9.199
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   589.043
_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  0.947  0.000  0.942  1.0
  K  K1  1  0.053  0.500  0.442  1.0
  K  K2  1  0.466  0.000  0.269  1.0
  K  K3  1  0.534  0.500  0.769  1.0
  Si  Si4  1  0.856  0.710  0.945  1.0
  Si  Si5  1  0.144  0.790  0.445  1.0
  Si  Si6  1  0.144  0.210  0.445  1.0
  Si  Si7  1  0.856  0.290  0.945  1.0
  Si  Si8  1  0.358  0.799  0.777  1.0
  Si  Si9  1  0.642  0.701  0.277  1.0
  Si  Si10  1  0.642  0.299  0.277  1.0
  Si  Si11  1  0.358  0.201  0.777  1.0
  Si  Si12  1  0.938  0.000  0.531  1.0
  Si  Si13  1  0.062  0.500  0.031  1.0
  B  B14  1  0.437  0.000  0.701  1.0
  B  B15  1  0.563  0.500  0.201  1.0
  O  O16  1  0.986  0.597  0.927  1.0
  O  O17  1  0.014  0.903  0.427  1.0
  O  O18  1  0.014  0.097  0.427  1.0
  O  O19  1  0.986  0.403  0.927  1.0
  O  O20  1  0.134  0.000  0.672  1.0
  O  O21  1  0.866  0.500  0.172  1.0
  O  O22  1  0.605  0.000  0.565  1.0
  O  O23  1  0.395  0.500  0.065  1.0
  O  O24  1  0.908  0.708  0.393  1.0
  O  O25  1  0.092  0.792  0.893  1.0
  O  O26  1  0.092  0.208  0.893  1.0
  O  O27  1  0.908  0.292  0.393  1.0
  O  O28  1  0.248  0.769  0.612  1.0
  O  O29  1  0.752  0.731  0.112  1.0
  O  O30  1  0.752  0.269  0.112  1.0
  O  O31  1  0.248  0.231  0.612  1.0
  O  O32  1  0.591  0.716  0.831  1.0
  O  O33  1  0.409  0.784  0.331  1.0
  O  O34  1  0.409  0.216  0.331  1.0
  O  O35  1  0.591  0.284  0.831  1.0
  O  O36  1  0.500  0.909  0.788  1.0
  O  O37  1  0.500  0.591  0.288  1.0
  O  O38  1  0.500  0.409  0.288  1.0
  O  O39  1  0.500  0.091  0.788  1.0
[/CIF]
.