Selenious acid
Selenous acid
CAS: 7783-00-8
Molecular Formula: H2O3Se
Selenious acid - Names and Identifiers
| Name | Selenous acid |
| Synonyms | Selenous acid Selenious acid seleniousacid10 Selenite, hydrogen seleniousacid(h2seo3) SELENIOUSACID,REAGENT Selenium dioxide, monohydrated |
| CAS | 7783-00-8 |
| EINECS | 231-974-7 |
| InChI | InChI=1/H2O3Se/c1-4(2)3/h(H2,1,2,3) |
Selenious acid - Physico-chemical Properties
| Molecular Formula | H2O3Se |
| Molar Mass | 128.97 |
| Density | 3.004 g/mL at 25 °C (lit.) |
| Melting Point | 70 °C (dec.) (lit.) |
| Boling Point | 684.9°C(lit.) |
| Flash Point | 690°C |
| Water Solubility | 167 g/100 mL (20 ºC) |
| Solubility | H2O: soluble |
| Vapor Presure | 2.7hPa at 15℃ |
| Appearance | powder |
| Specific Gravity | 3.004 |
| Color | White to almost white or light pink |
| Exposure Limit | ACGIH: TWA 0.2 mg/m3NIOSH: IDLH 1 mg/m3; TWA 0.2 mg/m3 |
| Merck | 14,8430 |
| pKa | 2.46(at 25℃) |
| PH | 3.15(1 mM solution);2.47(10 mM solution);1.9(100 mM solution) |
| Storage Condition | Store at RT. |
| Stability | Stable. |
| Sensitive | Hygroscopic |
| Physical and Chemical Properties | Colorless hexagonal crystals. Soluble in water. Soluble in ethanol. Insoluble in ammonia. |
Selenious acid - Risk and Safety
| Risk Codes | 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. R52/53 - Harmful to aquatic organisms, may cause long-term adverse effects in the aquatic environment. |
| Safety Description | S61 - Avoid release to the environment. Refer to special instructions / safety data sheets. S60 - This material and its container must be disposed of as hazardous waste. S45 - In case of accident or if you feel unwell, seek medical advice immediately (show the label whenever possible.) S28A - S20/21 - 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 soap-suds. |
| UN IDs | UN 3440 6.1/PG 3 |
| WGK Germany | 3 |
| RTECS | VS7700000 |
| FLUKA BRAND F CODES | 3 |
| TSCA | Yes |
| HS Code | 28111980 |
| Hazard Class | 8 |
| Packing Group | III |
Selenious acid - Reference Information
| EPA chemical substance information | information provided by: ofmpeb.epa.gov (external link) |
| purpose | can be used as oxidant and to prepare other selenium compounds, sodium selenite pharmaceutical intermediates, chemical reagents used as chemical reagents and reducing agents |
| production method | 1. At room temperature, nitric acid, a reagent having a density of 1.18, was reacted with selenium until no more nitrogen oxides overflowed, and the mixture was then evaporated to dryness at 50-60 °c. The obtained solid is dissolved in water and filtered, the filtrate is evaporated and concentrated to 1/4 of the original volume, then the crystals are cooled and crystallized, the crystals obtained by Suction filtration are washed with a small amount of ice water, and the washing solution and the filtrate are combined and recycled, the obtained crystals are recrystallized by the above method, and the reagent selenous acid can be obtained. 2. Dissolve pure SeO2 in a small amount of water in a porcelain dish, and concentrate the solution by evaporation in a water bath until crystallization begins (dust should be avoided during operation, otherwise it will be reduced to Se). After cooling, the precipitated selenous acid crystals are filtered with a glass sand core funnel, recrystallized once with water and then dried. The product was forced between two layers of filter paper and dried in a vacuum desiccator with KOH for several days. If concentrated sulfuric acid or phosphorus pentoxide is used as a desiccant, it may be further dehydrated into selenium dioxide for a long time. |
| category | toxic substances |
| toxicity grade | highly toxic |
| Acute toxicity | oral-rat LDL0: 25 mg/kg; Intravenous-mouse LD50: 11 mg/kg |
| flammability hazard characteristics | non-combustible material; Toxic selenide vapor |
| storage and transportation characteristics | The warehouse is ventilated and dried at low temperature; With alkali, acid and fine metal powder, separate storage of food additives |
| extinguishing agent | depending on the surrounding chemicals |
| Occupational Standard | TLA-TWA: 0.1 mg (selenium)/m3 |
| toxic substance data | information provided by: pubchem.ncbi.nlm.nih.gov (external link) |
Last Update：2024-04-10 22:29:15
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