TbGa crystallizes in the orthorhombic Cmcm space group. The structure is three-dimensional. Tb is bonded in a 7-coordinate geometry to seven equivalent Ga atoms. There are a spread of Tb–Ga bond distances ranging from 3.07–3.21 Å. Ga is bonded in a 9-coordinate geometry to seven equivalent Tb and two equivalent Ga atoms. Both Ga–Ga bond lengths are 2.63 Å.