Tb2B4C crystallizes in the orthorhombic Immm space group. Tb(1) is bonded in a 2-coordinate geometry to six equivalent B(1) and two equivalent C(1) atoms. There are two inequivalent B sites. In the first B site, B(1) is bonded in a 9-coordinate geometry to six equivalent Tb(1), one B(1), and two equivalent B(2) atoms. In the second B site, B(2) is bonded in a single-bond geometry to two equivalent B(1) and one C(1) atom. C(1) is bonded to four equivalent Tb(1) and two equivalent B(2) atoms to form distorted edge-sharing CTb4B2 octahedra.
Tb2B4C crystallizes in the orthorhombic Immm space group. Tb(1) is bonded in a 2-coordinate geometry to six equivalent B(1) and two equivalent C(1) atoms. There are four shorter (2.75 Å) and two longer (2.99 Å) Tb(1)-B(1) bond lengths. Both Tb(1)-C(1) bond lengths are 2.42 Å. There are two inequivalent B sites. In the first B site, B(1) is bonded in a 9-coordinate geometry to six equivalent Tb(1), one B(1), and two equivalent B(2) atoms. The B(1)-B(1) bond length is 1.77 Å. Both B(1)-B(2) bond lengths are 1.88 Å. In the second B site, B(2) is bonded in a single-bond geometry to two equivalent B(1) and one C(1) atom. The B(2)-C(1) bond length is 1.49 Å. C(1) is bonded to four equivalent Tb(1) and two equivalent B(2) atoms to form distorted edge-sharing CTb4B2 octahedra.