Thallium(I) hydroxide, also known as thallous hydroxide, is a chemical compound. Its chemical formula is TlOH. It has thallium and hydroxide ions in it. The thallium is in its +1 oxidation state.
Thallium(I) hydroxide is a yellow solid. It dissolves in water to make a yellow and very basic solution, similar to potassium hydroxide. It reacts with acids to make thallium salts. It breaks down to thallium(I) oxide when heated.
It is made by dissolving thallium(I) oxide in water or by reacting thallium with water or moist air.