Hydroperoxyl

Hydroperoxyl
Names
	Preferred IUPAC name Hydroperoxyl
	Systematic IUPAC name Dioxidanyl
	Other names Peroxyl radical, hydrogen superoxide, hydrogen dioxide
Identifiers
CAS Number	3170-83-0 ;
3D model (JSmol)	Interactive image;
ChEBI	CHEBI:25935;
ChemSpider	454055 ;
Gmelin Reference	506
PubChem CID	520535;
CompTox Dashboard (EPA)	DTXSID30894777 ;
	InChI InChI=1S/HO2/c1-2/h1H Key: OUUQCZGPVNCOIJ-UHFFFAOYSA-N ;
	SMILES [O]O;
Properties
Chemical formula	HO2
Molar mass	33.006 g·mol−1
Acidity (pKa)	4.88
Basicity (pKb)	9.12 (basicity of superoxide ion)
Conjugate base	Superoxide anion
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

The hydroperoxyl radical, also known as the hydrogen superoxide, is the protonated form of superoxide with the chemical formula HO₂, also written HOO^•. This species plays an important role in the atmosphere and as a reactive oxygen species in cell biology.^[2]

^ Bielski, Benon H. J.; Cabelli, Diane E.; Arudi, Ravindra L.; Ross, Alberta B. (1985). "Reactivity of HO₂/O⁻
₂ Radicals in Aqueous Solution". J. Phys. Chem. Ref. Data. 14 (4): 1041–1091. Bibcode:1985JPCRD..14.1041B. doi:10.1063/1.555739.
^ Heard, Dwayne E.; Pilling, Michael J. (2003). "Measurement of OH and HO₂ in the Troposphere". Chemical Reviews. 103 (12): 5163–5198. doi:10.1021/cr020522s. PMID 14664647.

[pka-1] Bielski, Benon H. J.; Cabelli, Diane E.; Arudi, Ravindra L.; Ross, Alberta B. (1985). "Reactivity of HO₂/O⁻
₂ Radicals in Aqueous Solution". J. Phys. Chem. Ref. Data. 14 (4): 1041–1091. Bibcode:1985JPCRD..14.1041B. doi:10.1063/1.555739.

[CR-2] Heard, Dwayne E.; Pilling, Michael J. (2003). "Measurement of OH and HO₂ in the Troposphere". Chemical Reviews. 103 (12): 5163–5198. doi:10.1021/cr020522s. PMID 14664647.

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