Tellurous acid is an

inorganic compound In chemistry, an inorganic compound is typically a chemical compound that lacks carbon–hydrogen bonds, that is, a compound that is not an organic compound. The study of inorganic compounds is a subfield of chemistry known as '' inorganic chemist ...

with the

formula In science, a formula is a concise way of expressing information symbolically, as in a mathematical formula or a ''chemical formula''. The informal use of the term ''formula'' in science refers to the general construct of a relationship betwee ...

H₂TeO₃. It is the

oxoacid An oxyacid, oxoacid, or ternary acid is an acid that contains oxygen. Specifically, it is a compound that contains hydrogen, oxygen, and at least one other element, with at least one hydrogen atom bonded to oxygen that can dissociate to produce ...

of tellurium(IV). This compound is not well characterized. An alternative way of writing its formula is (HO)₂TeO. In principle, tellurous acid would form by treatment of

tellurium dioxide Tellurium dioxide (TeO2) is a solid oxide of tellurium. It is encountered in two different forms, the yellow orthorhombic mineral tellurite, β-TeO2, and the synthetic, colourless tetragonal (paratellurite), α-TeO2. Most of the information regard ...

with water, that is by hydrolysis. The related conjugate base is well known in the form of several salts such as potassium hydrogen tellurite, KHTeO₃.

Properties

In contrast to the analogous compound

selenous acid Selenous acid (or selenious acid) is the chemical compound with the formula . Structurally, it is more accurately described by . It is the principal oxoacid of selenium; the other being selenic acid. Formation and properties Selenous acid is ana ...

, tellurous acid is only metastable. Most tellurite salts contain the ion. Oxidation of its aqueous solution with hydrogen peroxide gives the

tellurate In chemistry tellurate is a compound containing an oxyanion of tellurium where tellurium has an oxidation number of +6. In the naming of inorganic compounds it is a suffix that indicates a polyatomic anion with a central tellurium atom.

ion. It is usually prepared as an aqueous solution where it acts as a weak acid. :H₂TeO₃ + H₂O H₃O⁺ + ''K''_a1 = : + H₂O H₃O⁺ + ''K''_a2 =

References

Hydrogen compounds Tellurites Oxoacids {{inorganic-compound-stub