The sonication of InCl3 with thioacetamide in an aqueous solution has led to different products, depending on the sonication temperature. Sonication at 0 °C yielded In2O3 as the major product and In2S3 as a minor component. On the other hand, when the reaction is carried out at "room temperature", nanocrystalline In2S3 is obtained as the sole product. The products of sonication at 0 °C are obtained in the amorphous form. An explanation for this is offered based on the hot spot mechanism.