The compound described by K2GeSi6O15 crystallizes in the monoclinic Cc space group. There are two inequivalent K sites. In the first K site, K(1) is bonded in a 8-coordinate geometry to one O(10), one O(11), one O(14), one O(15), one O(2), one O(3), one O(5), and one O(9) atom. In the second K site, K(2) is bonded in a 7-coordinate geometry to one O(1), one O(10), one O(11), one O(12), one O(13), one O(3), and one O(4) atom. Ge(1) is bonded to one O(10), one O(11), one O(12), one O(13), one O(14), and one O(9) atom to form GeO6 octahedra that share  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(2)O4 tetrahedra,  a cornercorner with one Si(3)O4 tetrahedra,  a cornercorner with one Si(4)O4 tetrahedra,  a cornercorner with one Si(5)O4 tetrahedra, and  a cornercorner with one Si(6)O4 tetrahedra. There are six inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(1), one O(15), one O(7), and one O(9) atom to form SiO4 tetrahedra that share  a cornercorner with one Ge(1)O6 octahedra,  a cornercorner with one Si(4)O4 tetrahedra,  a cornercorner with one Si(5)O4 tetrahedra, and  a cornercorner with one Si(6)O4 tetrahedra. The corner-sharing octahedral tilt angles are 32°. In the second Si site, Si(2) is bonded to one O(12), one O(3), one O(6), and one O(8) atom to form SiO4 tetrahedra that share  a cornercorner with one Ge(1)O6 octahedra,  a cornercorner with one Si(3)O4 tetrahedra,  a cornercorner with one Si(5)O4 tetrahedra, and  a cornercorner with one Si(6)O4 tetrahedra. The corner-sharing octahedral tilt angles are 52°. In the third Si site, Si(3) is bonded to one O(13), one O(3), one O(4), and one O(5) atom to form SiO4 tetrahedra that share  a cornercorner with one Ge(1)O6 octahedra,  a cornercorner with one Si(2)O4 tetrahedra,  a cornercorner with one Si(4)O4 tetrahedra, and  a cornercorner with one Si(6)O4 tetrahedra. The corner-sharing octahedral tilt angles are 51°. In the fourth Si site, Si(4) is bonded to one O(1), one O(14), one O(2), and one O(5) atom to form SiO4 tetrahedra that share  a cornercorner with one Ge(1)O6 octahedra,  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(3)O4 tetrahedra, and  a cornercorner with one Si(5)O4 tetrahedra. The corner-sharing octahedral tilt angles are 49°. In the fifth Si site, Si(5) is bonded to one O(10), one O(15), one O(2), and one O(6) atom to form SiO4 tetrahedra that share  a cornercorner with one Ge(1)O6 octahedra,  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(2)O4 tetrahedra, and  a cornercorner with one Si(4)O4 tetrahedra. The corner-sharing octahedral tilt angles are 47°. In the sixth Si site, Si(6) is bonded to one O(11), one O(4), one O(7), and one O(8) atom to form SiO4 tetrahedra that share  a cornercorner with one Ge(1)O6 octahedra,  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(2)O4 tetrahedra, and  a cornercorner with one Si(3)O4 tetrahedra. The corner-sharing octahedral tilt angles are 41°. There are fifteen inequivalent O sites. In the first O site, O(1) is bonded in a distorted bent 150 degrees geometry to one K(2), one Si(1), and one Si(4) atom. In the second O site, O(2) is bonded in a distorted bent 120 degrees geometry to one K(1), one Si(4), and one Si(5) atom. In the third O site, O(3) is bonded in a distorted bent 120 degrees geometry to one K(1), one K(2), one Si(2), and one Si(3) atom. In the fourth O site, O(4) is bonded in a 2-coordinate geometry to one K(2), one Si(3), and one Si(6) atom. In the fifth O site, O(5) is bonded in a bent 150 degrees geometry to one K(1), one Si(3), and one Si(4) atom. In the sixth O site, O(6) is bonded in a linear geometry to one Si(2) and one Si(5) atom. In the seventh O site, O(7) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(6) atom. In the eighth O site, O(8) is bonded in a bent 150 degrees geometry to one Si(2) and one Si(6) atom. In the ninth O site, O(9) is bonded in a distorted bent 150 degrees geometry to one K(1), one Ge(1), and one Si(1) atom. In the tenth O site, O(10) is bonded in a 2-coordinate geometry to one K(1), one K(2), one Ge(1), and one Si(5) atom. In the eleventh O site, O(11) is bonded in a 2-coordinate geometry to one K(1), one K(2), one Ge(1), and one Si(6) atom. In the twelfth O site, O(12) is bonded in a 3-coordinate geometry to one K(2), one Ge(1), and one Si(2) atom. In the thirteenth O site, O(13) is bonded in a 2-coordinate geometry to one K(2), one Ge(1), and one Si(3) atom. In the fourteenth O site, O(14) is bonded in a distorted bent 120 degrees geometry to one K(1), one Ge(1), and one Si(4) atom. In the fifteenth O site, O(15) is bonded in a distorted bent 120 degrees geometry to one K(1), one Si(1), and one Si(5) atom. is represented by the CIF file [CIF]
data_K2Si6GeO15
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.349
_cell_length_b   7.349
_cell_length_c   15.008
_cell_angle_alpha   75.426
_cell_angle_beta   75.426
_cell_angle_gamma   59.530
_symmetry_Int_Tables_number   1
_cell_volume   668.702
_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  0.787  0.921  0.212  1.0
  K  K1  1  0.921  0.787  0.712  1.0
  K  K2  1  0.209  0.576  0.401  1.0
  K  K3  1  0.576  0.209  0.901  1.0
  Si  Si4  1  0.564  0.591  0.170  1.0
  Si  Si5  1  0.591  0.564  0.670  1.0
  Si  Si6  1  0.693  0.133  0.477  1.0
  Si  Si7  1  0.133  0.693  0.977  1.0
  Si  Si8  1  0.119  0.046  0.493  1.0
  Si  Si9  1  0.046  0.119  0.993  1.0
  Si  Si10  1  0.196  0.051  0.188  1.0
  Si  Si11  1  0.051  0.196  0.688  1.0
  Si  Si12  1  0.293  0.397  0.172  1.0
  Si  Si13  1  0.397  0.293  0.672  1.0
  Si  Si14  1  0.598  0.771  0.460  1.0
  Si  Si15  1  0.771  0.598  0.960  1.0
  Ge  Ge16  1  0.895  0.395  0.327  1.0
  Ge  Ge17  1  0.395  0.895  0.827  1.0
  O  O18  1  0.334  0.790  0.207  1.0
  O  O19  1  0.790  0.334  0.707  1.0
  O  O20  1  0.364  0.150  0.160  1.0
  O  O21  1  0.150  0.364  0.660  1.0
  O  O22  1  0.940  0.967  0.500  1.0
  O  O23  1  0.967  0.940  1.000  1.0
  O  O24  1  0.346  0.840  0.460  1.0
  O  O25  1  0.840  0.346  0.960  1.0
  O  O26  1  0.065  0.120  0.100  1.0
  O  O27  1  0.120  0.065  0.600  1.0
  O  O28  1  0.222  0.550  0.074  1.0
  O  O29  1  0.550  0.222  0.574  1.0
  O  O30  1  0.621  0.669  0.059  1.0
  O  O31  1  0.669  0.621  0.559  1.0
  O  O32  1  0.601  0.997  0.450  1.0
  O  O33  1  0.997  0.601  0.950  1.0
  O  O34  1  0.751  0.541  0.223  1.0
  O  O35  1  0.541  0.751  0.723  1.0
  O  O36  1  0.478  0.110  0.759  1.0
  O  O37  1  0.110  0.478  0.259  1.0
  O  O38  1  0.662  0.760  0.872  1.0
  O  O39  1  0.760  0.662  0.372  1.0
  O  O40  1  0.332  0.673  0.897  1.0
  O  O41  1  0.673  0.332  0.397  1.0
  O  O42  1  0.269  0.063  0.926  1.0
  O  O43  1  0.063  0.269  0.426  1.0
  O  O44  1  0.128  0.030  0.781  1.0
  O  O45  1  0.030  0.128  0.281  1.0
  O  O46  1  0.389  0.514  0.684  1.0
  O  O47  1  0.514  0.389  0.184  1.0
[/CIF]
.
The compound described by K2GeSi6O15 crystallizes in the monoclinic Cc space group. There are two inequivalent K sites. In the first K site, K(1) is bonded in a 8-coordinate geometry to one O(10), one O(11), one O(14), one O(15), one O(2), one O(3), one O(5), and one O(9) atom. In the second K site, K(2) is bonded in a 7-coordinate geometry to one O(1), one O(10), one O(11), one O(12), one O(13), one O(3), and one O(4) atom. Ge(1) is bonded to one O(10), one O(11), one O(12), one O(13), one O(14), and one O(9) atom to form GeO6 octahedra that share  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(2)O4 tetrahedra,  a cornercorner with one Si(3)O4 tetrahedra,  a cornercorner with one Si(4)O4 tetrahedra,  a cornercorner with one Si(5)O4 tetrahedra, and  a cornercorner with one Si(6)O4 tetrahedra. There are six inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(1), one O(15), one O(7), and one O(9) atom to form SiO4 tetrahedra that share  a cornercorner with one Ge(1)O6 octahedra,  a cornercorner with one Si(4)O4 tetrahedra,  a cornercorner with one Si(5)O4 tetrahedra, and  a cornercorner with one Si(6)O4 tetrahedra. The corner-sharing octahedral tilt angles are 32°. In the second Si site, Si(2) is bonded to one O(12), one O(3), one O(6), and one O(8) atom to form SiO4 tetrahedra that share  a cornercorner with one Ge(1)O6 octahedra,  a cornercorner with one Si(3)O4 tetrahedra,  a cornercorner with one Si(5)O4 tetrahedra, and  a cornercorner with one Si(6)O4 tetrahedra. The corner-sharing octahedral tilt angles are 52°. In the third Si site, Si(3) is bonded to one O(13), one O(3), one O(4), and one O(5) atom to form SiO4 tetrahedra that share  a cornercorner with one Ge(1)O6 octahedra,  a cornercorner with one Si(2)O4 tetrahedra,  a cornercorner with one Si(4)O4 tetrahedra, and  a cornercorner with one Si(6)O4 tetrahedra. The corner-sharing octahedral tilt angles are 51°. In the fourth Si site, Si(4) is bonded to one O(1), one O(14), one O(2), and one O(5) atom to form SiO4 tetrahedra that share  a cornercorner with one Ge(1)O6 octahedra,  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(3)O4 tetrahedra, and  a cornercorner with one Si(5)O4 tetrahedra. The corner-sharing octahedral tilt angles are 49°. In the fifth Si site, Si(5) is bonded to one O(10), one O(15), one O(2), and one O(6) atom to form SiO4 tetrahedra that share  a cornercorner with one Ge(1)O6 octahedra,  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(2)O4 tetrahedra, and  a cornercorner with one Si(4)O4 tetrahedra. The corner-sharing octahedral tilt angles are 47°. In the sixth Si site, Si(6) is bonded to one O(11), one O(4), one O(7), and one O(8) atom to form SiO4 tetrahedra that share  a cornercorner with one Ge(1)O6 octahedra,  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(2)O4 tetrahedra, and  a cornercorner with one Si(3)O4 tetrahedra. The corner-sharing octahedral tilt angles are 41°. There are fifteen inequivalent O sites. In the first O site, O(1) is bonded in a distorted bent 150 degrees geometry to one K(2), one Si(1), and one Si(4) atom. In the second O site, O(2) is bonded in a distorted bent 120 degrees geometry to one K(1), one Si(4), and one Si(5) atom. In the third O site, O(3) is bonded in a distorted bent 120 degrees geometry to one K(1), one K(2), one Si(2), and one Si(3) atom. In the fourth O site, O(4) is bonded in a 2-coordinate geometry to one K(2), one Si(3), and one Si(6) atom. In the fifth O site, O(5) is bonded in a bent 150 degrees geometry to one K(1), one Si(3), and one Si(4) atom. In the sixth O site, O(6) is bonded in a linear geometry to one Si(2) and one Si(5) atom. In the seventh O site, O(7) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(6) atom. In the eighth O site, O(8) is bonded in a bent 150 degrees geometry to one Si(2) and one Si(6) atom. In the ninth O site, O(9) is bonded in a distorted bent 150 degrees geometry to one K(1), one Ge(1), and one Si(1) atom. In the tenth O site, O(10) is bonded in a 2-coordinate geometry to one K(1), one K(2), one Ge(1), and one Si(5) atom. In the eleventh O site, O(11) is bonded in a 2-coordinate geometry to one K(1), one K(2), one Ge(1), and one Si(6) atom. In the twelfth O site, O(12) is bonded in a 3-coordinate geometry to one K(2), one Ge(1), and one Si(2) atom. In the thirteenth O site, O(13) is bonded in a 2-coordinate geometry to one K(2), one Ge(1), and one Si(3) atom. In the fourteenth O site, O(14) is bonded in a distorted bent 120 degrees geometry to one K(1), one Ge(1), and one Si(4) atom. In the fifteenth O site, O(15) is bonded in a distorted bent 120 degrees geometry to one K(1), one Si(1), and one Si(5) atom. is represented by the CIF file [CIF]
data_K2Si6GeO15
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.349
_cell_length_b   7.349
_cell_length_c   15.008
_cell_angle_alpha   75.426
_cell_angle_beta   75.426
_cell_angle_gamma   59.530
_symmetry_Int_Tables_number   1
_cell_volume   668.702
_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  0.787  0.921  0.212  1.0
  K  K1  1  0.921  0.787  0.712  1.0
  K  K2  1  0.209  0.576  0.401  1.0
  K  K3  1  0.576  0.209  0.901  1.0
  Si  Si4  1  0.564  0.591  0.170  1.0
  Si  Si5  1  0.591  0.564  0.670  1.0
  Si  Si6  1  0.693  0.133  0.477  1.0
  Si  Si7  1  0.133  0.693  0.977  1.0
  Si  Si8  1  0.119  0.046  0.493  1.0
  Si  Si9  1  0.046  0.119  0.993  1.0
  Si  Si10  1  0.196  0.051  0.188  1.0
  Si  Si11  1  0.051  0.196  0.688  1.0
  Si  Si12  1  0.293  0.397  0.172  1.0
  Si  Si13  1  0.397  0.293  0.672  1.0
  Si  Si14  1  0.598  0.771  0.460  1.0
  Si  Si15  1  0.771  0.598  0.960  1.0
  Ge  Ge16  1  0.895  0.395  0.327  1.0
  Ge  Ge17  1  0.395  0.895  0.827  1.0
  O  O18  1  0.334  0.790  0.207  1.0
  O  O19  1  0.790  0.334  0.707  1.0
  O  O20  1  0.364  0.150  0.160  1.0
  O  O21  1  0.150  0.364  0.660  1.0
  O  O22  1  0.940  0.967  0.500  1.0
  O  O23  1  0.967  0.940  1.000  1.0
  O  O24  1  0.346  0.840  0.460  1.0
  O  O25  1  0.840  0.346  0.960  1.0
  O  O26  1  0.065  0.120  0.100  1.0
  O  O27  1  0.120  0.065  0.600  1.0
  O  O28  1  0.222  0.550  0.074  1.0
  O  O29  1  0.550  0.222  0.574  1.0
  O  O30  1  0.621  0.669  0.059  1.0
  O  O31  1  0.669  0.621  0.559  1.0
  O  O32  1  0.601  0.997  0.450  1.0
  O  O33  1  0.997  0.601  0.950  1.0
  O  O34  1  0.751  0.541  0.223  1.0
  O  O35  1  0.541  0.751  0.723  1.0
  O  O36  1  0.478  0.110  0.759  1.0
  O  O37  1  0.110  0.478  0.259  1.0
  O  O38  1  0.662  0.760  0.872  1.0
  O  O39  1  0.760  0.662  0.372  1.0
  O  O40  1  0.332  0.673  0.897  1.0
  O  O41  1  0.673  0.332  0.397  1.0
  O  O42  1  0.269  0.063  0.926  1.0
  O  O43  1  0.063  0.269  0.426  1.0
  O  O44  1  0.128  0.030  0.781  1.0
  O  O45  1  0.030  0.128  0.281  1.0
  O  O46  1  0.389  0.514  0.684  1.0
  O  O47  1  0.514  0.389  0.184  1.0
[/CIF]
.