A single-phase material (HfMg)(WO4)(3) with an orthorhombic structure, A(2) (WO4)(3)-type tungstate, has been successfully prepared for the first time by the calcination of HfO2, MgO, and WO3, substituting Hf4+ and Mg2+ for A(3+) cations in A(2)(WO4)(3). The new material shows a negative thermal expansion coefficient of approximately -2 ppm/degreesC from room temperature to 800degreesC. The mechanism of negative thermal expansion is assumed to be the same as that of Sc-2(WO4)(3).