| Identification | More | [Name]
Selenious acid | [CAS]
7783-00-8 | [Synonyms]
SELENIOUS ACID
SELENIUM
SELENIUM AA/ICP CALIBRATION/CHECK STANDARD
SELENIUM AA SINGLE ELEMENT STANDARD
SELENIUM, AAS STANDARD SOLUTION
SELENIUM AA STANDARD
SELENIUM ATOMIC ABSORPTION SINGLE ELEMENT STANDARD
SELENIUM ATOMIC ABSORPTION STANDARD
SELENIUM ATOMIC ABSORPTION STANDARD SOLUTION
SELENIUM ATOMIC SPECTROSCOPY STANDARD
SELENIUM DIOXIDE, HYDRATED
SELENIUM ICP/DCP STANDARD
SELENIUM ICP STANDARD
SELENIUM METAL
SELENIUM METALLO-ORGANIC STANDARD
SELENIUM MIXTURE
SELENIUM PLASMA EMISSION SPECTROSCOPY STANDARD
SELENIUM PLASMA EMISSION STANDARD
SELENIUM, PLASMA STANDARD SOLUTION
SELENIUM, POWDER | [EINECS(EC#)]
231-957-4 | [Molecular Formula]
H2O3Se | [MDL Number]
MFCD00134090 | [Molecular Weight]
128.97 | [MOL File]
7783-00-8.mol |
| Chemical Properties | Back Directory | [Description]
Selenious acid is a colourless, deliquescent crystal in appearance. It decomposes on heating,
producing water and toxic fumes of selenium oxides.
It is incompatible with strong reducing agents, organic materials, and finely powdered
metals and reacts on contact with acids producing toxic gaseous hydrogen selenide.
Selenious acid is a non-combustible chemical. On fire/burning, it emits irritating or toxic
fumes (or gases).
The major use of selenious acid is in changing the colour of steel, especially the steel in
guns from silver grey to blue grey. It is also used for the chemical darkening and patination
of copper brass and bronze, producing a rich dark-brown colour that can be further
enhanced with mechanical abrasion. | [Appearance]
Selenious acid is a colorless, crystalline solid. | [Melting point ]
70 °C (dec.) (lit.) | [Boiling point ]
684.9 °C(lit.) | [density ]
4.81 g/mL at 25 °C(lit.)
| [vapor pressure ]
2.7hPa at 15℃ | [Fp ]
690°C | [storage temp. ]
Store at RT. | [solubility ]
H2O: soluble
| [form ]
powder
| [pka]
2.46(at 25℃) | [color ]
White to almost white or light pink | [Specific Gravity]
3.004 | [PH]
3.15(1 mM solution);2.47(10 mM solution);1.9(100 mM solution) | [Stability:]
Stable. | [Water Solubility ]
167 g/100 mL (20 ºC) | [Sensitive ]
Hygroscopic | [Merck ]
14,8430 | [Exposure limits]
ACGIH: TWA 0.2 mg/m3
NIOSH: IDLH 1 mg/m3; TWA 0.2 mg/m3 | [CAS DataBase Reference]
7783-00-8(CAS DataBase Reference) | [EPA Substance Registry System]
7783-00-8(EPA Substance) |
| Safety Data | Back Directory | [Hazard Codes ]
T,N,Xi | [Risk Statements ]
R36/38:Irritating to eyes and skin .
R50/53:Very Toxic to aquatic organisms, may cause long-term adverse effects in the aquatic environment .
R33:Danger of cumulative effects.
R23/25:Toxic by inhalation and if swallowed . | [Safety Statements ]
S61:Avoid release to the environment. Refer to special instructions safety data sheet .
S60:This material and/or its container must be disposed of as hazardous waste .
S45:In case of accident or if you feel unwell, seek medical advice immediately (show label where possible) .
S20/21:When using, do not eat, drink or smoke .
S26:In case of contact with eyes, rinse immediately with plenty of water and seek medical advice .
S28:After contact with skin, wash immediately with plenty of ... (to be specified by the manufacturer) . | [RIDADR ]
UN 3440 6.1/PG 3
| [WGK Germany ]
3
| [RTECS ]
VS7700000
| [F ]
3 | [TSCA ]
Yes | [HazardClass ]
8 | [PackingGroup ]
III | [HS Code ]
28111980 | [Safety Profile]
Poison by ingestion, intraperitoneal, and intravenous routes. Human mutation data reported. Used as an oxidizing agent. When heated to decomposition it emits toxic fumes of Se. See also SELENIUM COMPOUNDS | [Hazardous Substances Data]
7783-00-8(Hazardous Substances Data) |
| Hazard Information | Back Directory | [General Description]
Colorless solid, transparent, colorless crystals. Used as a reagent for alkaloids and as an oxidizing agent. Isotope is used in labeling radiopharmaceuticals. | [Reactivity Profile]
SELENIOUS ACID decomposes when heated to toxic and volatile selenium dioxide. Serves as an oxidizing agent. Reacts exothermically with many reducing agents including hydroiodic acid, sulfurous acid, sodium hyposulfite, hydroxylamine salts, hydrazine salts, hypophosphorous acid, phosphorous acid [Merck]. Oxidizes many organic substances. Is oxidized to selenic acid by strong oxidizing agents. | [Hazard]
Toxic by inhalation, ingestion, and skin
absorption.
| [Health Hazard]
Selenious acid and its salts are capable of penetrating the skin and can produce acute poisonings. Causes irritations and burns of the skin. It is highly toxic orally. Inorganic selenium compounds may cause dermatitis. | [Potential Exposure]
Selenious acid is used as a reagent for alkaloids and as an oxidizing agent. Isotope is used in labeling radiopharmaceuticals. | [Fire Hazard]
When heated to decomposition SELENIOUS ACID emits toxic fumes of selenium. Avoid heating. | [First aid]
Move victim to fresh air. Call 911 or emergency medical service. Give artificial respiration if victim is not breathing. Do not use mouth-to-mouth method if victim ingested or inhaled the substance; give artificial respiration with the aid of a pocket mask equipped with a one-way valve or other proper respiratory medical device. Administer oxygen if breathing is difficult. Remove and isolate contaminated clothing and shoes. In case of contact with substance, immediately flush skin or eyes with running water for at least 20 minutes. For minor skin contact, avoid spreading material on unaffected skin. Keep victim warm and quiet. Effects of exposure (inhalation, ingestion or skin contact) to substance may be delayed. Ensure that medical personnel are aware of the material(s) involved and take precautions to protect themselves. Medical observation is recommended for 24 to 48 hours after breathing overexposure, as pulmonary edema may be delayed. As first aid for pulmonary edema, a doctor or authorized paramedic may consider administering a drug or other inhalation therapy | [Shipping]
UN3283Selenium compound, solid, n.o.s., Hazard Class: 6.1; Labels: 6.1-Poisonous material, Technical Name Required. UN3440 Selenium compound, liquid, n.o.s., Hazard Class: 6.1; Labels: 6.1-Poisonous material, Technical Name Required. | [Incompatibilities]
A strong oxidizer. Reacts exothermically with many reducing agents including hydroiodic acid, sulfurous acid, sodium hyposulfite, hydroxylamine salts, hydrazine salts, hypophosphorous acid, phosphorous acid. Incompatible combustibles, organic material, oxidizable materials, strong acids, strong bases. Contact with acids produce toxic and gaseous hydrogen selenide. Attacks metals. | [Chemical Properties]
Selenious acid is a colorless, crystalline solid. | [Chemical Properties]
White solid | [Waste Disposal]
Consult with environmental regulatory agencies for guidance on acceptable disposal practices. Generators of waste containing this contaminant (≥100 kg/mo) must conform to EPA regulations governing storage, transportation, treatment, and waste disposal. | [Uses]
As a reagent for alkaloids; as oxidizing agent. | [Uses]
As an oxidizing agent, as a reagent for alkaloidsSelenous acid is used in steel guns, wherein it changes the color of the steel from silver-grey to blue-grey. It serves as an important component of the Mecke reagent, which is utilized for drug testing. It acts as a source of selenium. It acts as a reagent for alkaloids and an oxidizing agent. Further, it is used in labeling radiopharmaceuticals. It is involved in the organic synthesis for the preparation of glyoxal. | [Definition]
ChEBI: Selenous acid is a selenium oxoacid. It is a conjugate acid of a hydrogenselenite. | [Purification Methods]
Recrystallise the acid from water. On heating it loses water and SeO2 sublimes. [Waitkins & Clark Chem Rev 36 235 1945.] |
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