Tm2Fe12P7 crystallizes in the hexagonal P-6 space group. There are two inequivalent Tm sites. In the first Tm site, Tm(1) is bonded in a 6-coordinate geometry to six equivalent P(2) atoms. In the second Tm site, Tm(2) is bonded in a 15-coordinate geometry to three equivalent Fe(3), six equivalent Fe(1), and six equivalent P(1) atoms. There are four inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to two equivalent Tm(2), two equivalent P(1), and two equivalent P(2) atoms to form distorted FeTm2P4 tetrahedra that share corners with four equivalent Fe(2)P4 tetrahedra, corners with four equivalent Fe(1)Tm2P4 tetrahedra, corners with four equivalent Fe(3)TmP4 tetrahedra,  an edgeedge with one Fe(2)P4 tetrahedra, edges with two equivalent Fe(1)Tm2P4 tetrahedra, edges with two equivalent Fe(3)TmP4 tetrahedra, faces with two equivalent Fe(1)Tm2P4 tetrahedra, and faces with two equivalent Fe(3)TmP4 tetrahedra. In the second Fe site, Fe(2) is bonded to one P(1), one P(3), and two equivalent P(2) atoms to form distorted FeP4 tetrahedra that share corners with two equivalent Fe(3)TmP4 tetrahedra, corners with four equivalent Fe(2)P4 tetrahedra, corners with four equivalent Fe(1)Tm2P4 tetrahedra,  an edgeedge with one Fe(1)Tm2P4 tetrahedra, and edges with two equivalent Fe(3)TmP4 tetrahedra. In the third Fe site, Fe(3) is bonded to one Tm(2), two equivalent P(1), and two equivalent P(2) atoms to form distorted FeTmP4 tetrahedra that share corners with two equivalent Fe(2)P4 tetrahedra, corners with four equivalent Fe(1)Tm2P4 tetrahedra, corners with six equivalent Fe(3)TmP4 tetrahedra, edges with two equivalent Fe(2)P4 tetrahedra, edges with two equivalent Fe(1)Tm2P4 tetrahedra, and faces with two equivalent Fe(1)Tm2P4 tetrahedra. In the fourth Fe site, Fe(4) is bonded in a 5-coordinate geometry to one P(2), two equivalent P(1), and two equivalent P(3) atoms. There are three inequivalent P sites. In the first P site, P(1) is bonded in a 9-coordinate geometry to two equivalent Tm(2), one Fe(2), two equivalent Fe(1), two equivalent Fe(3), and two equivalent Fe(4) atoms. In the second P site, P(2) is bonded in a 9-coordinate geometry to two equivalent Tm(1), one Fe(4), two equivalent Fe(1), two equivalent Fe(2), and two equivalent Fe(3) atoms. In the third P site, P(3) is bonded in a 9-coordinate geometry to three equivalent Fe(2) and six equivalent Fe(4) atoms.
Tm2Fe12P7 crystallizes in the hexagonal P-6 space group. There are two inequivalent Tm sites. In the first Tm site, Tm(1) is bonded in a 6-coordinate geometry to six equivalent P(2) atoms. All Tm(1)-P(2) bond lengths are 2.79 Å. In the second Tm site, Tm(2) is bonded in a 15-coordinate geometry to three equivalent Fe(3), six equivalent Fe(1), and six equivalent P(1) atoms. All Tm(2)-Fe(3) bond lengths are 3.03 Å. All Tm(2)-Fe(1) bond lengths are 3.02 Å. All Tm(2)-P(1) bond lengths are 2.82 Å. There are four inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to two equivalent Tm(2), two equivalent P(1), and two equivalent P(2) atoms to form distorted FeTm2P4 tetrahedra that share corners with four equivalent Fe(2)P4 tetrahedra, corners with four equivalent Fe(1)Tm2P4 tetrahedra, corners with four equivalent Fe(3)TmP4 tetrahedra,  an edgeedge with one Fe(2)P4 tetrahedra, edges with two equivalent Fe(1)Tm2P4 tetrahedra, edges with two equivalent Fe(3)TmP4 tetrahedra, faces with two equivalent Fe(1)Tm2P4 tetrahedra, and faces with two equivalent Fe(3)TmP4 tetrahedra. Both Fe(1)-P(1) bond lengths are 2.32 Å. Both Fe(1)-P(2) bond lengths are 2.37 Å. In the second Fe site, Fe(2) is bonded to one P(1), one P(3), and two equivalent P(2) atoms to form distorted FeP4 tetrahedra that share corners with two equivalent Fe(3)TmP4 tetrahedra, corners with four equivalent Fe(2)P4 tetrahedra, corners with four equivalent Fe(1)Tm2P4 tetrahedra,  an edgeedge with one Fe(1)Tm2P4 tetrahedra, and edges with two equivalent Fe(3)TmP4 tetrahedra. The Fe(2)-P(1) bond length is 2.20 Å. The Fe(2)-P(3) bond length is 2.17 Å. Both Fe(2)-P(2) bond lengths are 2.24 Å. In the third Fe site, Fe(3) is bonded to one Tm(2), two equivalent P(1), and two equivalent P(2) atoms to form distorted FeTmP4 tetrahedra that share corners with two equivalent Fe(2)P4 tetrahedra, corners with four equivalent Fe(1)Tm2P4 tetrahedra, corners with six equivalent Fe(3)TmP4 tetrahedra, edges with two equivalent Fe(2)P4 tetrahedra, edges with two equivalent Fe(1)Tm2P4 tetrahedra, and faces with two equivalent Fe(1)Tm2P4 tetrahedra. Both Fe(3)-P(1) bond lengths are 2.27 Å. There is one shorter (2.29 Å) and one longer (2.33 Å) Fe(3)-P(2) bond length. In the fourth Fe site, Fe(4) is bonded in a 5-coordinate geometry to one P(2), two equivalent P(1), and two equivalent P(3) atoms. The Fe(4)-P(2) bond length is 2.40 Å. Both Fe(4)-P(1) bond lengths are 2.49 Å. Both Fe(4)-P(3) bond lengths are 2.50 Å. There are three inequivalent P sites. In the first P site, P(1) is bonded in a 9-coordinate geometry to two equivalent Tm(2), one Fe(2), two equivalent Fe(1), two equivalent Fe(3), and two equivalent Fe(4) atoms. In the second P site, P(2) is bonded in a 9-coordinate geometry to two equivalent Tm(1), one Fe(4), two equivalent Fe(1), two equivalent Fe(2), and two equivalent Fe(3) atoms. In the third P site, P(3) is bonded in a 9-coordinate geometry to three equivalent Fe(2) and six equivalent Fe(4) atoms.