Subsolidus phase relationships within the ZnO-In<sub>2</sub>O<sub>3</sub>-SnO<sub>2</sub> system at 1275 <sup>o</sup>C were established by conventional solid state reaction methods. No new compounds or structures were observed within the ternary diagram. Equilibrium in the ZnO-corner, between the homologous compounds and the spinel phase, was found difficult to achieve. This problem was overcome...