Phase relationships and crystal structure in the pseudobinary system La5Si4-La5Ge4

► La5Si4−xGex crystallizes in Zr5Si4-type tetragonal structure for 0 ⩽ x ⩽ 2.9. ► La5Si4−xGex with 3.1 ⩽ x ⩽ 4 adopts a Sm5Ge4-type orthorhombic structure. ► The structure transition are induced by the atomic size difference between Si and Ge.