Ca7Tl3N2 crystallizes in the orthorhombic Cmmm space group. There are four inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a linear geometry to two equivalent Tl(1), two equivalent Tl(2), and two equivalent N(1) atoms. In the second Ca site, Ca(2) is bonded in a single-bond geometry to six equivalent Tl(2) and one N(1) atom. In the third Ca site, Ca(3) is bonded in a linear geometry to four equivalent Tl(1) and two equivalent N(1) atoms. In the fourth Ca site, Ca(4) is bonded in a linear geometry to two equivalent Tl(1), two equivalent Tl(2), and two equivalent N(1) atoms. There are two inequivalent Tl sites. In the first Tl site, Tl(1) is bonded to four equivalent Ca(1), four equivalent Ca(3), and four equivalent Ca(4) atoms to form TlCa12 cuboctahedra that share corners with four equivalent Tl(1)Ca12 cuboctahedra, corners with eight equivalent Tl(2)Ca10Tl2 cuboctahedra, faces with two equivalent Tl(2)Ca10Tl2 cuboctahedra, faces with four equivalent Tl(1)Ca12 cuboctahedra, and faces with eight equivalent N(1)Ca6 octahedra. In the second Tl site, Tl(2) is bonded to two equivalent Ca(1), two equivalent Ca(4), six equivalent Ca(2), and two equivalent Tl(2) atoms to form distorted TlCa10Tl2 cuboctahedra that share corners with four equivalent Tl(2)Ca10Tl2 cuboctahedra, corners with four equivalent Tl(1)Ca12 cuboctahedra, corners with two equivalent N(1)Ca6 octahedra, edges with four equivalent Tl(2)Ca10Tl2 cuboctahedra,  a faceface with one Tl(1)Ca12 cuboctahedra, faces with six equivalent Tl(2)Ca10Tl2 cuboctahedra, and faces with four equivalent N(1)Ca6 octahedra. The corner-sharing octahedral tilt angles are 45°. N(1) is bonded to one Ca(2), one Ca(3), two equivalent Ca(1), and two equivalent Ca(4) atoms to form NCa6 octahedra that share corners with two equivalent Tl(2)Ca10Tl2 cuboctahedra, corners with five equivalent N(1)Ca6 octahedra, faces with four equivalent Tl(2)Ca10Tl2 cuboctahedra, and faces with four equivalent Tl(1)Ca12 cuboctahedra. The corner-sharing octahedral tilt angles range from 0-5°.
Ca7Tl3N2 crystallizes in the orthorhombic Cmmm space group. There are four inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a linear geometry to two equivalent Tl(1), two equivalent Tl(2), and two equivalent N(1) atoms. Both Ca(1)-Tl(1) bond lengths are 3.46 Å. Both Ca(1)-Tl(2) bond lengths are 3.58 Å. Both Ca(1)-N(1) bond lengths are 2.47 Å. In the second Ca site, Ca(2) is bonded in a single-bond geometry to six equivalent Tl(2) and one N(1) atom. There are two shorter (3.41 Å) and four longer (3.47 Å) Ca(2)-Tl(2) bond lengths. The Ca(2)-N(1) bond length is 2.33 Å. In the third Ca site, Ca(3) is bonded in a linear geometry to four equivalent Tl(1) and two equivalent N(1) atoms. All Ca(3)-Tl(1) bond lengths are 3.46 Å. Both Ca(3)-N(1) bond lengths are 2.53 Å. In the fourth Ca site, Ca(4) is bonded in a linear geometry to two equivalent Tl(1), two equivalent Tl(2), and two equivalent N(1) atoms. Both Ca(4)-Tl(1) bond lengths are 3.46 Å. Both Ca(4)-Tl(2) bond lengths are 3.64 Å. Both Ca(4)-N(1) bond lengths are 2.43 Å. There are two inequivalent Tl sites. In the first Tl site, Tl(1) is bonded to four equivalent Ca(1), four equivalent Ca(3), and four equivalent Ca(4) atoms to form TlCa12 cuboctahedra that share corners with four equivalent Tl(1)Ca12 cuboctahedra, corners with eight equivalent Tl(2)Ca10Tl2 cuboctahedra, faces with two equivalent Tl(2)Ca10Tl2 cuboctahedra, faces with four equivalent Tl(1)Ca12 cuboctahedra, and faces with eight equivalent N(1)Ca6 octahedra. In the second Tl site, Tl(2) is bonded to two equivalent Ca(1), two equivalent Ca(4), six equivalent Ca(2), and two equivalent Tl(2) atoms to form distorted TlCa10Tl2 cuboctahedra that share corners with four equivalent Tl(2)Ca10Tl2 cuboctahedra, corners with four equivalent Tl(1)Ca12 cuboctahedra, corners with two equivalent N(1)Ca6 octahedra, edges with four equivalent Tl(2)Ca10Tl2 cuboctahedra,  a faceface with one Tl(1)Ca12 cuboctahedra, faces with six equivalent Tl(2)Ca10Tl2 cuboctahedra, and faces with four equivalent N(1)Ca6 octahedra. The corner-sharing octahedral tilt angles are 45°. Both Tl(2)-Tl(2) bond lengths are 3.27 Å. N(1) is bonded to one Ca(2), one Ca(3), two equivalent Ca(1), and two equivalent Ca(4) atoms to form NCa6 octahedra that share corners with two equivalent Tl(2)Ca10Tl2 cuboctahedra, corners with five equivalent N(1)Ca6 octahedra, faces with four equivalent Tl(2)Ca10Tl2 cuboctahedra, and faces with four equivalent Tl(1)Ca12 cuboctahedra. The corner-sharing octahedral tilt angles range from 0-5°.