The structures and thermal expansion properties of Lu2-xFexMo3O12 have been investigated by X-ray diffraction （XRD）. XRD patterns at room temperature indicate that compounds Lu2-xFexMo3O12 with x ≤ 1.3 exhibit an orthorhombic structure with space group Pnca; compounds with x = 1.5 and 1.7 have a monoclinic structure with space group P21/a. Studies on thermal expansion properties show that the linear thermal expansion coefficients of orthorhombic phase vary from negative to positive with increasing Fe content. Attempts to make zero thermal expansion materials indicate that zero thermal expansion can be observed in Lu1.3Fe0.7Mo3O12 in the temperature range of 200 400 ℃.
