MgTb4(PO4)4 crystallizes in the triclinic P1 space group. Mg(1) is bonded in a 5-coordinate geometry to one O(1), one O(11), one O(14), one O(3), and one O(5) atom. There are four inequivalent Tb sites. In the first Tb site, Tb(1) is bonded in a 5-coordinate geometry to one O(10), one O(13), one O(4), one O(8), and one O(9) atom. In the second Tb site, Tb(2) is bonded in a 7-coordinate geometry to one O(12), one O(13), one O(14), one O(2), one O(3), one O(6), 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(16), one O(2), one O(3), 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(15), 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 tetrahedral geometry to one O(1), one O(13), one O(5), 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 3-coordinate geometry to one Mg(1), one Tb(2), one Tb(3), and one P(3) atom. In the fourth O site, O(4) is bonded in a distorted trigonal non-coplanar geometry to one Tb(1), one Tb(4), and one P(4) atom. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to one Mg(1), one Tb(4), and one P(1) atom. In the sixth O site, O(6) is bonded in a 2-coordinate geometry to one Tb(2), one Tb(3), and one P(2) atom. In the seventh O site, O(7) is bonded in a distorted trigonal non-coplanar geometry to one Tb(2), one Tb(3), and one P(3) atom. In the eighth O site, O(8) is bonded in a distorted bent 120 degrees geometry to one Tb(1) and one P(4) atom. In the ninth O site, O(9) is bonded in a 3-coordinate geometry to one Tb(1), 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(1), one Tb(4), and one P(2) atom. In the eleventh O site, O(11) is bonded in a distorted T-shaped geometry to one Mg(1), one Tb(3), and one P(3) atom. In the twelfth O site, O(12) is bonded in a 3-coordinate geometry to one Tb(2), one Tb(4), and one P(4) atom. In the thirteenth O site, O(13) is bonded in a distorted T-shaped geometry to one Tb(1), one Tb(2), and one P(1) atom. In the fourteenth O site, O(14) is bonded in a 3-coordinate geometry to one Mg(1), one Tb(2), and one P(2) atom. In the fifteenth O site, O(15) is bonded in a bent 150 degrees geometry to one Tb(4) 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.
MgTb4(PO4)4 crystallizes in the triclinic P1 space group. Mg(1) is bonded in a 5-coordinate geometry to one O(1), one O(11), one O(14), one O(3), and one O(5) atom. The Mg(1)-O(1) bond length is 2.37 Å. The Mg(1)-O(11) bond length is 2.12 Å. The Mg(1)-O(14) bond length is 2.08 Å. The Mg(1)-O(3) bond length is 2.21 Å. The Mg(1)-O(5) bond length is 2.16 Å. There are four inequivalent Tb sites. In the first Tb site, Tb(1) is bonded in a 5-coordinate geometry to one O(10), one O(13), one O(4), one O(8), and one O(9) atom. The Tb(1)-O(10) bond length is 2.44 Å. The Tb(1)-O(13) bond length is 2.42 Å. The Tb(1)-O(4) bond length is 2.40 Å. The Tb(1)-O(8) bond length is 2.25 Å. The Tb(1)-O(9) bond length is 2.44 Å. In the second Tb site, Tb(2) is bonded in a 7-coordinate geometry to one O(12), one O(13), one O(14), one O(2), one O(3), one O(6), and one O(7) atom. The Tb(2)-O(12) bond length is 2.32 Å. The Tb(2)-O(13) bond length is 2.35 Å. The Tb(2)-O(14) bond length is 2.48 Å. The Tb(2)-O(2) bond length is 2.36 Å. The Tb(2)-O(3) bond length is 2.35 Å. The Tb(2)-O(6) bond length is 2.73 Å. The Tb(2)-O(7) bond length is 2.36 Å. In the third Tb site, Tb(3) is bonded in a 7-coordinate geometry to one O(11), one O(16), one O(2), one O(3), one O(6), one O(7), and one O(9) atom. The Tb(3)-O(11) bond length is 2.29 Å. The Tb(3)-O(16) bond length is 2.32 Å. The Tb(3)-O(2) bond length is 2.59 Å. The Tb(3)-O(3) bond length is 2.78 Å. The Tb(3)-O(6) bond length is 2.35 Å. The Tb(3)-O(7) bond length is 2.44 Å. The Tb(3)-O(9) bond length is 2.37 Å. 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(15), one O(16), one O(4), and one O(5) atom. The Tb(4)-O(1) bond length is 2.29 Å. The Tb(4)-O(10) bond length is 2.48 Å. The Tb(4)-O(12) bond length is 2.45 Å. The Tb(4)-O(15) bond length is 2.19 Å. The Tb(4)-O(16) bond length is 2.59 Å. The Tb(4)-O(4) bond length is 2.38 Å. The Tb(4)-O(5) bond length is 2.33 Å. There are four inequivalent P sites. In the first P site, P(1) is bonded in a tetrahedral geometry to one O(1), one O(13), one O(5), and one O(9) atom. The P(1)-O(1) bond length is 1.55 Å. The P(1)-O(13) bond length is 1.55 Å. The P(1)-O(5) bond length is 1.57 Å. The P(1)-O(9) bond length is 1.55 Å. 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. The P(2)-O(10) bond length is 1.57 Å. The P(2)-O(14) bond length is 1.55 Å. The P(2)-O(2) bond length is 1.57 Å. The P(2)-O(6) bond length is 1.57 Å. 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. The P(3)-O(11) bond length is 1.55 Å. The P(3)-O(15) bond length is 1.52 Å. The P(3)-O(3) bond length is 1.58 Å. The P(3)-O(7) bond length is 1.56 Å. 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. The P(4)-O(12) bond length is 1.57 Å. The P(4)-O(16) bond length is 1.56 Å. The P(4)-O(4) bond length is 1.56 Å. The P(4)-O(8) bond length is 1.53 Å. 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 3-coordinate geometry to one Mg(1), one Tb(2), one Tb(3), and one P(3) atom. In the fourth O site, O(4) is bonded in a distorted trigonal non-coplanar geometry to one Tb(1), one Tb(4), and one P(4) atom. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to one Mg(1), one Tb(4), and one P(1) atom. In the sixth O site, O(6) is bonded in a 2-coordinate geometry to one Tb(2), one Tb(3), and one P(2) atom. In the seventh O site, O(7) is bonded in a distorted trigonal non-coplanar geometry to one Tb(2), one Tb(3), and one P(3) atom. In the eighth O site, O(8) is bonded in a distorted bent 120 degrees geometry to one Tb(1) and one P(4) atom. In the ninth O site, O(9) is bonded in a 3-coordinate geometry to one Tb(1), 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(1), one Tb(4), and one P(2) atom. In the eleventh O site, O(11) is bonded in a distorted T-shaped geometry to one Mg(1), one Tb(3), and one P(3) atom. In the twelfth O site, O(12) is bonded in a 3-coordinate geometry to one Tb(2), one Tb(4), and one P(4) atom. In the thirteenth O site, O(13) is bonded in a distorted T-shaped geometry to one Tb(1), one Tb(2), and one P(1) atom. In the fourteenth O site, O(14) is bonded in a 3-coordinate geometry to one Mg(1), one Tb(2), and one P(2) atom. In the fifteenth O site, O(15) is bonded in a bent 150 degrees geometry to one Tb(4) 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.