CAS number 14332-28-6
PubChem 945
ChemSpider 920 YesY
MeSH Nitroxyl
Jmol-3D images Image 1
Molecular formula HNO
Molar mass 31.01 g mol−1
Exact mass 31.005813659 g mol-1
log P 0.74
Molecular shape Dihedral
Standard molar
220.91 J K-1 mol-1
Specific heat capacity, C 33.88 J K-1 mol-1
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Nitroxyl is the chemical compound HNO. It is well known in the gas phase [1]. In aqueous solution it acts as an acid with the conjugate base NO, (pKa = 11.4).[2] NO is the reduced form of nitric oxide (NO) and is isoelectronic with dioxygen. Nitroxyl can be formed as a reaction intermediate.
Nitroxyl is very reactive towards nucleophiles (especially thiols) and quickly dimerizes to hyponitrous acid, H2N2O2, which is then dehydrated to nitrous oxide N2O. Therefore, HNO is generally prepared in situ for example with the compounds such as Angeli’s salt (Na2N2O3) and Piloty’s acid (PhSO2NHOH) when it is needed.

Nitroxyl shows potential in the treatment of heart failure and ongoing research is focused on finding new nitroxyl donors. In one study [3] such donor is prepared by organic oxidation of cyclohexanone oxime with lead tetraacetate to 1-nitrosocyclohexyl acetate:

Nitrosocyclohexyl acetate

This compound can be hydrolyzed under basic conditions in a phosphate buffer to nitroxyl HNO, acetic acid and cyclohexanone.

Other studies that have been conducted on HNO precursors include those from Nagasawa et al. [4] in which Piloty's acid is derivatized and produces HNO upon thermal decomposition. Other notable studies on the production of HNO come from Toscano et al.[5] in which cycloadducts of acyl nitroso species (which are known to decompose via hydrolysis to HNO and acyl acid) are synthesized. Upon photolysis these compounds release the acyl nitroso species which then further decomposes.


  1. ^ Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Oxford: Butterworth-Heinemann. ISBN 0080379419. 
  2. ^ Egon Wiberg, Arnold Frederick Holleman (2001) Inorganic Chemistry, Elsevier ISBN 0-12-352651-5
  3. ^ Hydrolysis of Acyloxy Nitroso Compounds Yields Nitroxyl (HNO) Xin Sha, T. Scott Isbell, Rakesh P. Patel, Cynthia S. Day, and S. Bruce King J. Am. Chem. Soc.; 2006; 128(30) pp 9687 - 9692; (Article) doi: 10.1021/ja062365a
  4. ^ Prodrugs of Nitroxyl as Potential Aldehyde Dehydrogenase Inhibitors vis-a-vis Vascular Smooth Muscle Relaxants Nagasawa, H. T.; Kawle, S. P.; Elberling, J. A.; DeMaster, E. G.; Fukuto, J. M. J. Med. Chem., 38, 1865-1871. doi:10.1021/jm00011a005
  5. ^ Cohen, A. D.; Zeng, B.-B.; King, S. B.; Toscano, J. P. J. Am. Chem. Soc. 2003, 125, 1444-1445.doi:10.1021/ja028978e

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Look at other dictionaries:

  • Nitroxyl — Ni*trox yl, n. [Nitro + oxygen + yl.] (Chem.) The group { NO2}, usually called the {nitro group}. [1913 Webster] …   The Collaborative International Dictionary of English

  • nitroxyl — nitro i tro pref. 1. A combining form or an adjective denoting the presence of niter. [1913 Webster] 2. (Chem.) A combining form (used also adjectively) designating certain compounds of nitrogen or of its acids; as nitrohydrochloric,… …   The Collaborative International Dictionary of English

  • nitroxyl — noun Aminoxyl …   Wiktionary

  • nitroxyl — The nitrosyl hydride, HNO. * * * ni·trox·yl (ni trokґsəl) nitryl …   Medical dictionary

  • Nitroxyl- — Ni|t|ro|xyl [↑ Nitr u. ↑ oxyl] veraltete Bez. in der org. Chemie für die Gruppierung =NO· (↑ Aminoxyl, ↑ Nitroxid) u. in der anorg. Chemie für das Kation NO+2 (↑ Nitryl ) …   Universal-Lexikon

  • nitroxyl — ni·trox·yl …   English syllables

  • nitroxyl — nī.ˈträksə̇l noun Etymology: International Scientific Vocabulary nitr + oxy + yl : nitryl …   Useful english dictionary

  • nitro group — Nitroxyl Ni*trox yl, n. [Nitro + oxygen + yl.] (Chem.) The group { NO2}, usually called the {nitro group}. [1913 Webster] …   The Collaborative International Dictionary of English

  • -NO2 — Nitroxyl Ni*trox yl, n. [Nitro + oxygen + yl.] (Chem.) The group { NO2}, usually called the {nitro group}. [1913 Webster] …   The Collaborative International Dictionary of English

  • Нитроксильные радикалы — Нитроксильные радикалы  органические радикалы, содержащие нитроксильную группу N O·. Впервые открыты в 1951 г.[1] Первый синтез соединения 2,2,6,6 тетраметил 4 пиперидон 1 оксил (4 оксо TEMPO) был выполнен О.Л. Лебедевым в 1959 г.[2]… …   Википедия

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