Hydrogen polyoxides (also known as oxidanes or oxohydrogens) are chemical compounds that consist only of hydrogen and oxygen atoms and are bonded exclusively by single bonds (i.e. they are saturated compounds) without any cycles (or loops i.e. cyclic structure). Hydrogen polyoxides belong to a homologous series of inorganic compounds in which the members differ by a constant relative molecular mass of 16.
Each oxygen atom has two bonds (either O-H or O-O bonds), and each hydrogen atom is joined to an oxygen atom (H-O bonds). A series of linked oxygen atoms is known as the oxygen skeleton or oxygen backbone. The number of oxygen atoms is used to define the size of the hydrogen polyoxide (e.g., hydrogen pentoxide).
An oxidanyl group is a functional group or side-chain, that like a hydrogen polyoxide, consists solely of single-bonded oxygen and hydrogen atoms, for example a hydroxy (oxidyl) or hydroperoxy (dioxidanyl) group.
The simplest possible hydrogen polyoxide (the parent molecule) is water, H2O. There is no limit to the number of oxygen atoms that can be linked together, the only limitation being that the molecule is acyclic, and is a hydrooxygen.
Hydrooxygens are linear (general formula H
n) wherein the oxygen atoms are joined in a snakelike structure.
The hydrogen polyoxides
- Water (H2O) is the most common hydrogen polyoxide, occurring widely on Earth's surface.
- Hydrogen peroxide (H2O2) is a common disinfectant and readily decomposes to form water and oxygen.
- Trioxidane (H2O3) is rare and readily decomposes into water and singlet oxygen.
- Hydrogen tetroxide (H2O4) has not been detected.
- Hydrogen pentoxide (H2O5) is a byproduct of trioxidane production.
All of the hydrogen polyoxides autoionise when in liquid form, producing HOn− and H+(H2On), better known as H3On+.
- Xin Xu and William A. Goddard III. Peroxonechemistry: Formation of H2O3 and ring-(HO2)(HO3) from O3/H2O2