A low thermal-expansion material was synthesized with potential application in thermal-shock-resistant infrared-transmitting windows. The material is derived from a solid solution of Al-2(WO4)(3), which has positive thermal expansion, and Sc-2(WO4)(3) with a negative thermal expansion. An optimum composition of Al0.5Sc1.5(WO4)(3) was identified by synthesizing solid solutions, Al2-x Sc (x) (WO4)(3), by a solid-state route with compositions ranging from x = 0 to 2.0. A single orthorhombic phase was obtained at all compositions. A composition corresponding to x = 1.5 had a low coefficient of thermal expansion of -0.15 x 10(-6)/A degrees C in the temperature range 25-700 A degrees C. A low temperature solution combustion process was developed for this optimum composition, resulting in a single-phase powder with a surface area of similar to 4 m(2)/g and average particle size (as determined from surface area) of 92 nm. The powder was consolidated by slip-casting, sintering, and hot-isostatic pressing into visibly translucent disks with a peak in-line transmittance of 73 % at 2300 cm(-1). Significant infrared absorption in a 1-mm-thick disk of this material begins near 2200 cm(-1) and features three absorptions arising from 2-phonon transitions at 2002, 1847, and 1676 cm(-1). The infrared and Raman spectra are interpreted in terms of 1-, 2-, and 3-phonon vibrational transitions.