Orthorhombic In2Mo3O12 has low negative linear coefficient of thermal expansion (alpha(1) = -1.85 x 10(-6) degrees C-1)as evaluated by X-ray powder diffraction using a synchrotron facility. The linear coefficient of thermal expansion for orthorhombic In2Mo3O12 is directly dependent on the inherent volume distortion parameter (upsilon) of InO6. This finding strongly corroborates the recently proposed relationship between the linear coefficient of thermal expansion in A(2)M(3)O(12) compounds (alpha(1)) and the distortion level of AO(6) polyhedra. With the increase of inherent distortion parameter (upsilon) of AO(6) polyhedra, the linear coefficient of thermal expansion becomes more negative. Another important feature of AO(6) polyhedra, including InO6, is that their distortion increases as a function of temperature. Orthorhombic In2Mo3O12 is stable in the Studied temperature range, 370-760 degrees C. (C) 2009 Elsevier B.V. All rights reserved.