The material structure described by MgTb4(PO4)4 crystallizes in the triclinic P1 space group. Mg(1) is bonded in a see-saw-like geometry to one O(1), one O(15), one O(6), and one O(8) atom. There are four inequivalent Tb sites. In the first Tb site, Tb(1) is bonded in a 6-coordinate geometry to one O(11), one O(13), one O(14), one O(4), one O(5), and one O(8) atom. In the second Tb site, Tb(2) is bonded in a 7-coordinate geometry to one O(10), one O(12), one O(14), one O(2), one O(3), one O(5), and one O(7) atom. In the third Tb site, Tb(3) is bonded in a 7-coordinate geometry to one O(11), one O(15), one O(16), one O(2), one O(6), one O(7), and one O(9) atom. In the fourth Tb site, Tb(4) is bonded in a 7-coordinate geometry to one O(1), one O(10), one O(12), one O(13), one O(16), one O(4), and one O(5) atom. There are four inequivalent P sites. In the first P site, P(1) is bonded in a trigonal non-coplanar geometry to one O(1), one O(13), and one O(9) atom. In the second P site, P(2) is bonded in a tetrahedral geometry to one O(10), one O(14), one O(2), and one O(6) atom. In the third P site, P(3) is bonded in a tetrahedral geometry to one O(11), one O(15), one O(3), and one O(7) atom. In the fourth P site, P(4) is bonded in a tetrahedral geometry to one O(12), one O(16), one O(4), and one O(8) atom. There are sixteen inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one Mg(1), one Tb(4), and one P(1) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Tb(2), one Tb(3), and one P(2) atom. In the third O site, O(3) is bonded in a distorted bent 150 degrees geometry to one Tb(2) and one P(3) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Tb(1), one Tb(4), and one P(4) atom. In the fifth O site, O(5) is bonded in a distorted T-shaped geometry to one Tb(1), one Tb(2), and one Tb(4) atom. In the sixth O site, O(6) is bonded in a 3-coordinate geometry to one Mg(1), one Tb(3), and one P(2) atom. In the seventh O site, O(7) is bonded in a 3-coordinate geometry to one Tb(2), one Tb(3), and one P(3) atom. In the eighth O site, O(8) is bonded in a 3-coordinate geometry to one Mg(1), one Tb(1), and one P(4) atom. In the ninth O site, O(9) is bonded in a distorted bent 150 degrees geometry to one Tb(3) and one P(1) atom. In the tenth O site, O(10) is bonded in a 3-coordinate geometry to one Tb(2), one Tb(4), and one P(2) atom. In the eleventh O site, O(11) is bonded in a 3-coordinate geometry to one Tb(1), one Tb(3), and one P(3) atom. In the twelfth O site, O(12) is bonded in a distorted single-bond geometry to one Tb(2), one Tb(4), and one P(4) atom. In the thirteenth O site, O(13) is bonded in a 3-coordinate geometry to one Tb(1), one Tb(4), and one P(1) atom. In the fourteenth O site, O(14) is bonded in a 3-coordinate geometry to one Tb(1), one Tb(2), and one P(2) atom. In the fifteenth O site, O(15) is bonded in a 3-coordinate geometry to one Mg(1), one Tb(3), and one P(3) atom. In the sixteenth O site, O(16) is bonded in a 3-coordinate geometry to one Tb(3), one Tb(4), and one P(4) atom. is represented by the CIF file [CIF]
data_Tb4Mg(PO4)4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.368
_cell_length_b   8.274
_cell_length_c   6.634
_cell_angle_alpha   90.227
_cell_angle_beta   84.454
_cell_angle_gamma   108.443
_symmetry_Int_Tables_number   1
_cell_volume   329.882
_cell_formula_units_Z   1
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
  Tb  Tb0  1  0.377  0.134  0.724  1.0
  Tb  Tb1  1  0.971  0.746  0.944  1.0
  Tb  Tb2  1  0.589  0.892  0.292  1.0
  Tb  Tb3  1  0.008  0.285  0.017  1.0
  Mg  Mg4  1  0.278  0.496  0.456  1.0
  P  P5  1  0.934  0.212  0.583  1.0
  P  P6  1  0.426  0.712  0.821  1.0
  P  P7  1  0.084  0.791  0.418  1.0
  P  P8  1  0.564  0.322  0.171  1.0
  O  O9  1  0.004  0.324  0.374  1.0
  O  O10  1  0.606  0.730  0.968  1.0
  O  O11  1  0.974  0.694  0.613  1.0
  O  O12  1  0.387  0.309  0.021  1.0
  O  O13  1  0.047  0.033  0.920  1.0
  O  O14  1  0.495  0.688  0.595  1.0
  O  O15  1  0.911  0.814  0.281  1.0
  O  O16  1  0.469  0.344  0.390  1.0
  O  O17  1  0.756  0.040  0.530  1.0
  O  O18  1  0.211  0.561  0.883  1.0
  O  O19  1  0.267  0.963  0.452  1.0
  O  O20  1  0.780  0.466  0.102  1.0
  O  O21  1  0.782  0.283  0.742  1.0
  O  O22  1  0.358  0.876  0.852  1.0
  O  O23  1  0.227  0.691  0.291  1.0
  O  O24  1  0.630  0.152  0.154  1.0
[/CIF]
.
The material structure described by MgTb4(PO4)4 crystallizes in the triclinic P1 space group. Mg(1) is bonded in a see-saw-like geometry to one O(1), one O(15), one O(6), and one O(8) atom. There are four inequivalent Tb sites. In the first Tb site, Tb(1) is bonded in a 6-coordinate geometry to one O(11), one O(13), one O(14), one O(4), one O(5), and one O(8) atom. In the second Tb site, Tb(2) is bonded in a 7-coordinate geometry to one O(10), one O(12), one O(14), one O(2), one O(3), one O(5), and one O(7) atom. In the third Tb site, Tb(3) is bonded in a 7-coordinate geometry to one O(11), one O(15), one O(16), one O(2), one O(6), one O(7), and one O(9) atom. In the fourth Tb site, Tb(4) is bonded in a 7-coordinate geometry to one O(1), one O(10), one O(12), one O(13), one O(16), one O(4), and one O(5) atom. There are four inequivalent P sites. In the first P site, P(1) is bonded in a trigonal non-coplanar geometry to one O(1), one O(13), and one O(9) atom. In the second P site, P(2) is bonded in a tetrahedral geometry to one O(10), one O(14), one O(2), and one O(6) atom. In the third P site, P(3) is bonded in a tetrahedral geometry to one O(11), one O(15), one O(3), and one O(7) atom. In the fourth P site, P(4) is bonded in a tetrahedral geometry to one O(12), one O(16), one O(4), and one O(8) atom. There are sixteen inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one Mg(1), one Tb(4), and one P(1) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Tb(2), one Tb(3), and one P(2) atom. In the third O site, O(3) is bonded in a distorted bent 150 degrees geometry to one Tb(2) and one P(3) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Tb(1), one Tb(4), and one P(4) atom. In the fifth O site, O(5) is bonded in a distorted T-shaped geometry to one Tb(1), one Tb(2), and one Tb(4) atom. In the sixth O site, O(6) is bonded in a 3-coordinate geometry to one Mg(1), one Tb(3), and one P(2) atom. In the seventh O site, O(7) is bonded in a 3-coordinate geometry to one Tb(2), one Tb(3), and one P(3) atom. In the eighth O site, O(8) is bonded in a 3-coordinate geometry to one Mg(1), one Tb(1), and one P(4) atom. In the ninth O site, O(9) is bonded in a distorted bent 150 degrees geometry to one Tb(3) and one P(1) atom. In the tenth O site, O(10) is bonded in a 3-coordinate geometry to one Tb(2), one Tb(4), and one P(2) atom. In the eleventh O site, O(11) is bonded in a 3-coordinate geometry to one Tb(1), one Tb(3), and one P(3) atom. In the twelfth O site, O(12) is bonded in a distorted single-bond geometry to one Tb(2), one Tb(4), and one P(4) atom. In the thirteenth O site, O(13) is bonded in a 3-coordinate geometry to one Tb(1), one Tb(4), and one P(1) atom. In the fourteenth O site, O(14) is bonded in a 3-coordinate geometry to one Tb(1), one Tb(2), and one P(2) atom. In the fifteenth O site, O(15) is bonded in a 3-coordinate geometry to one Mg(1), one Tb(3), and one P(3) atom. In the sixteenth O site, O(16) is bonded in a 3-coordinate geometry to one Tb(3), one Tb(4), and one P(4) atom. is represented by the CIF file [CIF]
data_Tb4Mg(PO4)4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.368
_cell_length_b   8.274
_cell_length_c   6.634
_cell_angle_alpha   90.227
_cell_angle_beta   84.454
_cell_angle_gamma   108.443
_symmetry_Int_Tables_number   1
_cell_volume   329.882
_cell_formula_units_Z   1
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
  Tb  Tb0  1  0.377  0.134  0.724  1.0
  Tb  Tb1  1  0.971  0.746  0.944  1.0
  Tb  Tb2  1  0.589  0.892  0.292  1.0
  Tb  Tb3  1  0.008  0.285  0.017  1.0
  Mg  Mg4  1  0.278  0.496  0.456  1.0
  P  P5  1  0.934  0.212  0.583  1.0
  P  P6  1  0.426  0.712  0.821  1.0
  P  P7  1  0.084  0.791  0.418  1.0
  P  P8  1  0.564  0.322  0.171  1.0
  O  O9  1  0.004  0.324  0.374  1.0
  O  O10  1  0.606  0.730  0.968  1.0
  O  O11  1  0.974  0.694  0.613  1.0
  O  O12  1  0.387  0.309  0.021  1.0
  O  O13  1  0.047  0.033  0.920  1.0
  O  O14  1  0.495  0.688  0.595  1.0
  O  O15  1  0.911  0.814  0.281  1.0
  O  O16  1  0.469  0.344  0.390  1.0
  O  O17  1  0.756  0.040  0.530  1.0
  O  O18  1  0.211  0.561  0.883  1.0
  O  O19  1  0.267  0.963  0.452  1.0
  O  O20  1  0.780  0.466  0.102  1.0
  O  O21  1  0.782  0.283  0.742  1.0
  O  O22  1  0.358  0.876  0.852  1.0
  O  O23  1  0.227  0.691  0.291  1.0
  O  O24  1  0.630  0.152  0.154  1.0
[/CIF]
.