Tellurium trioxide

Tellurium trioxide, also known as tellurium(VI) oxide is a chemical compound. Its chemical formula is TeO3. It contains tellurium and oxide ions. It contains tellurium in its +6 oxidation state.
Properties.
Tellurium trioxide can come in two forms. There is a yellow-red form and a gray form. The yellow red form is more reactive. It is a powerful oxidizing agent. It reacts with strong bases to make tellurates. It releases oxygen to turn into tellurium dioxide when heated.
Preparation.
It is made by taking the water from telluric acid. The gray form can be made from this by reacting the yellow-red form with sulfuric acid and air.