Thiourea dioxide or thiox is an organosulfur compound that is used in the textile industry. It functions as a reducing agent. Thiourea dioxide is not a dioxide, but instead is a derivative of a sulfinic acid (RS(O)(OH), hence the alternative name formamidine sulfinic acid.
Thiourea dioxide is used in reductive bleaching in textiles. Thiourea dioxide has also been used for the reduction of aromatic nitroaldehydes and nitroketones to nitroalcohols.
| Properties | |
| Molecular formula | CH4N2O2S |
| Molar mass | 108.12 g mol−1 |
| Appearance | White powder |
| Melting point | 126 °C; 259 °F; 399 K |
| Solubility in water | 3.0 g/100 mL |