Tantalum pentoxide, also known as tantalum(V) oxide, is the inorganic compound with the formula Ta2O5. It is a white solid that is insoluble in all solvents but is attacked by strong bases and hydrofluoric acid.Ta2O5 is an inert material with a high refractive index and low absorption (i.e. colourless), which makes it useful for coatings.It is also extensively used in the production of capacitors, due to its highdielectric constant.