Thorium dioxide (ThO2), also called thorium(IV) oxide is a white, crystalline powder. It was formerly known as thoria or thorina. It is produced mainly as a by-product of lanthanide and uranium production.[1] Thorianite is the name of the mineralogical form of thorium dioxide. It is moderately rare and crystallizes in isometric system. Chemistry The compound is radioactive due to the radioactivity of thorium. Thorium dioxide can be used as a nuclear fuel. (Refer to the article of thorium for mo… (More on Thoria)