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Record Information
Version2.0
Creation Date2009-06-22 16:08:41 UTC
Update Date2014-12-24 20:24:43 UTC
Accession NumberT3D1837
Identification
Common NameSelenous acid
ClassSmall Molecule
DescriptionSelenous acid is the principal oxoacid of selenium. It is used in organic synthesis. Selenium is a nonmetal element with the atomic number 34 and the chemical symbol Se. Selenium rarely occurs in its elemental state in nature and is usually found in sulfide ores such as pyrite, partially replacing the sulfur in the ore matrix. It may also be found in silver, copper, lead, and nickel minerals. Though selenium salts are toxic in large amounts, trace amounts of the element are necessary for cellular function in most animals, forming the active center of the enzymes glutathione peroxidase, thioredoxin reductase, and three known deiodinase enzymes. (4, 5)
Compound Type
  • Industrial/Workplace Toxin
  • Inorganic Compound
  • Pollutant
  • Selenium Compound
  • Synthetic Compound
Chemical Structure
Thumb
Synonyms
Synonym
Dihydroxidooxidoselenium
Hydrogen selenite
Monohydrated selenium dioxide
Selenige saeure
Selenious acid
Selenious acid (H2seo3)
SELENIOUS ACID, H2SeO3
Selenium dioxide
Selenium dioxide, monohydrated
[SeO(OH)2]
Chemical FormulaH2O3Se
Average Molecular Mass128.970 g/mol
Monoisotopic Mass129.917 g/mol
CAS Registry Number7783-00-8
IUPAC Nameselenous acid
Traditional Nameselenious acid
SMILESO[Se](O)=O
InChI IdentifierInChI=1S/H2O3Se/c1-4(2)3/h(H2,1,2,3)
InChI KeyInChIKey=MCAHWIHFGHIESP-UHFFFAOYSA-N
Chemical Taxonomy
Description belongs to the class of inorganic compounds known as non-metal selenites. These are inorganic non-metallic compounds containing a selenite as its largest oxoanion.
KingdomInorganic compounds
Super ClassMixed metal/non-metal compounds
ClassOther mixed metal/non-metal oxoanionic compounds
Sub ClassNon-metal selenites
Direct ParentNon-metal selenites
Alternative Parents
Substituents
  • Non-metal selenite
  • Inorganic oxide
Molecular FrameworkNot Available
External Descriptors
Biological Properties
StatusDetected and Not Quantified
OriginExogenous
Cellular Locations
  • Cytoplasm
  • Extracellular
Biofluid LocationsNot Available
Tissue LocationsNot Available
PathwaysNot Available
ApplicationsNot Available
Biological RolesNot Available
Chemical RolesNot Available
Physical Properties
StateSolid
AppearanceColorless crystals.
Experimental Properties
PropertyValue
Melting Point70°C
Boiling PointNot Available
SolubilityNot Available
LogPNot Available
Predicted Properties
PropertyValueSource
logP-1.3ChemAxon
pKa (Strongest Acidic)1.2ChemAxon
Physiological Charge-2ChemAxon
Hydrogen Acceptor Count4ChemAxon
Hydrogen Donor Count2ChemAxon
Polar Surface Area57.53 ŲChemAxon
Rotatable Bond Count0ChemAxon
Refractivity19.69 m³·mol⁻¹ChemAxon
Polarizability5.84 ųChemAxon
Number of Rings0ChemAxon
Bioavailability1ChemAxon
Rule of FiveYesChemAxon
Ghose FilterYesChemAxon
Veber's RuleYesChemAxon
MDDR-like RuleYesChemAxon
Spectra
Spectra
Spectrum TypeDescriptionSplash KeyView
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 10V, Positivesplash10-001i-0900000000-0a19b2c40c0bb312f5beJSpectraViewer
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 20V, Positivesplash10-001i-0900000000-2d351128f9b2f20dfe09JSpectraViewer
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 40V, Positivesplash10-001i-1900000000-05c2bdb35a9b9c97cdb2JSpectraViewer
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 10V, Negativesplash10-004i-0900000000-325ef2a28e83bf8a1866JSpectraViewer
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 20V, Negativesplash10-004i-1900000000-d86c195af2b279d0f220JSpectraViewer
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 40V, Negativesplash10-004i-0900000000-86606fe3b82690787969JSpectraViewer
Toxicity Profile
Route of ExposureOral (3) ; inhalation (3) ; dermal (3)
Mechanism of ToxicitySelenium readily substitutes for sulfur in biomolecules and in many biochemical reactions, especially when the concentration of selenium is high and the concentration of sulfur is low. Inactivation of the sulfhydryl enzymes necessary for oxidative reactions in cellular respiration, through effects on mitochondrial and microsomal electron transport, might contribute to acute selenium toxicity. Selenomethionine (a common organic selenium compound) also appears to randomly substitute for methionine in protein synthesis. This substitution may affect the structure and functionability of the protein, for example, by altering disulfide bridges. Inorganic forms of selenium appear to react with tissue thiols by redox catalysis, resulting in formation of reactive oxygen species and causing damage by oxidative stress. (3)
MetabolismSelenium may be absorbed through inhalation and ingestion, while some selenium compounds may also be absorbed dermally. Once in the body, selenium is distributed mainly to the liver and kidney. Selenium is an essential micronutrient and is a component of glutathione peroxidase, iodothyronine 5'-deiodinases, and thioredoxin reductase. Organic selenium is first metabolized into inorganic selenium. Inorganic selenium is reduced stepwise to the intermediate hydrogen selenide, which is either incorporated into selenoproteins after being transformed to selenophosphate and selenocysteinyl tRNA or excreted into the urine after being transformed into methylated metabolites of selenide. Elemental selenium is also methylated before excretion. Selenium is primarily eliminated in the urine and feces, but certain selenium compounds may also be exhaled. (3)
Toxicity ValuesNot Available
Lethal DoseNot Available
Carcinogenicity (IARC Classification)3, not classifiable as to its carcinogenicity to humans. (2)
Uses/SourcesSelenous acid is used in organic synthesis. (5)
Minimum Risk LevelChronic Oral: 0.005 mg/kg/day (1)
Health EffectsChronic oral exposure to high concentrations of selenium compounds can produce a disease called selenosis. The major signs of selenosis are hair loss, nail brittleness, and neurological abnormalities (such as numbness and other odd sensations in the extremities). Animal studies have shown that selenium may also affect sperm production and the female reproductive cycle. (3)
SymptomsShort-term oral exposure to high concentrations of selenium may cause nausea, vomiting, and diarrhea. Brief exposures to high levels of elemental selenium or selenium dioxide in air can result in respiratory tract irritation, bronchitis, difficulty breathing, and stomach pains. Longer-term exposure to either of these air-borne forms can cause respiratory irritation, bronchial spasms, and coughing. (3)
TreatmentEYES: irrigate opened eyes for several minutes under running water. INGESTION: do not induce vomiting. Rinse mouth with water (never give anything by mouth to an unconscious person). Seek immediate medical advice. SKIN: should be treated immediately by rinsing the affected parts in cold running water for at least 15 minutes, followed by thorough washing with soap and water. If necessary, the person should shower and change contaminated clothing and shoes, and then must seek medical attention. INHALATION: supply fresh air. If required provide artificial respiration.
Normal Concentrations
Not Available
Abnormal Concentrations
Not Available
DrugBank IDNot Available
HMDB IDNot Available
PubChem Compound ID1091
ChEMBL IDCHEMBL2009089
ChemSpider ID1060
KEGG IDNot Available
UniProt IDNot Available
OMIM ID
ChEBI ID26642
BioCyc IDNot Available
CTD IDD020887
Stitch IDSelenous acid
PDB IDNot Available
ACToR ID6529
Wikipedia LinkNot Available
References
Synthesis ReferenceNot Available
MSDST3D1837.pdf
General References
  1. ATSDR - Agency for Toxic Substances and Disease Registry (2001). Minimal Risk Levels (MRLs) for Hazardous Substances. U.S. Public Health Service in collaboration with U.S. Environmental Protection Agency (EPA). [Link]
  2. International Agency for Research on Cancer (2014). IARC Monographs on the Evaluation of Carcinogenic Risks to Humans. [Link]
  3. ATSDR - Agency for Toxic Substances and Disease Registry (2003). Toxicological profile for selenium. U.S. Public Health Service in collaboration with U.S. Environmental Protection Agency (EPA). [Link]
  4. Wikipedia. Selenium. Last Updated 7 June 2009. [Link]
  5. Wikipedia. Selenous acid. Last Updated 30 July 2008. [Link]
Gene Regulation
Up-Regulated GenesNot Available
Down-Regulated GenesNot Available