Orthorhombic In sub(2Mo) sub(3)O sub(12 has low negative linear coefficient of thermal expansion ( alpha ) sub(l) = -1.85 x 10super-6 degCsuper-1) as evaluated by X-ray powder diffraction using a synchrotron facility. The linear coefficient of thermal expansion for orthorhombic In sub(2Mo) sub(3)O sub(12 is directly dependent on the inherent volume distortion parameter (upsilon) of InO) sub(6). This finding strongly corroborates the recently proposed relationship between the linear coefficient of thermal expansion in A sub(2M) sub(3)O sub(12 compounds ( alpha ) sub(l)) and the distortion level of AO sub(6 polyhedra. With the increase of inherent distortion parameter (upsilon) of AO) sub(6) polyhedra, the linear coefficient of thermal expansion becomes more negative. Another important feature of AO sub(6 polyhedra, including InO) sub(6), is that their distortion increases as a function of temperature. Orthorhombic In sub(2Mo) sub(3)O sub(12 is stable in the studied temperature range, 370-760 degC.)