Titanic acid is a general name for a family of chemical compounds of the elements titanium, hydrogen, and oxygen, with the general formula [TiO_x(OH)_4−2x]_n. Various simple titanic acids have been claimed, mainly in the older literature. No crystallographic and little spectroscopic support exists for these materials. Some older literature refers to titanium dioxide (TiO₂) as titanic acid, and the dioxide forms an unstable hydrate when TiCl₄ hydrolyzes.