Selenous acid
Also known as: Selenious acid, Monohydrated selenium dioxide, Selenium dioxide, monohydrated, Selenious acid (H2SeO3)
Selenous acid (CAS 7783-00-8) is a compound in the Inorganic Chemicals category listed in the Jingsj chemical database. It has the molecular formula H2O3Se and a molecular weight of 128.97400 g/mol. Key properties include a melting point of 70ºC, a boiling point of 684.9ºC(lit.), a density of 4.81 g/mL at 25ºC(lit.) and a flash point of 690°C. It is classified under GHS with signal word Danger and hazard statements H301 — Toxic if swallowed, H331 — Toxic if inhaled and H373 — May cause damage to organs through prolonged exposure. It is listed by 1 supplier, from 4.40 to 14.40 CNY. Record last updated Aug 21, 2026.
- CAS No.
- 7783-00-8
- Jingsj CID
- J-47054-0
- Molecular Formula
- H2O3Se
- Molecular Weight
- 128.97400 g/mol
- Category
- Inorganic Chemicals
- Last updated
- 8/21/2026
| Supplier | Purity / Pack | Base Price | Unit Price | Origin | |
|---|---|---|---|---|---|
Made to OrderPlatform-operated | 99% 500g | ¥2,200.00 | $0.66 /gBest ¥4.40/g CNY | CN China MOQ 500g | |
Made to OrderPlatform-operated | 99% 100g | ¥800.00 | $1.2 /g ¥8.00/g CNY | CN China MOQ 100g | |
Made to OrderPlatform-operated | 99% 25g | ¥360.00 | $2.15 /g ¥14.40/g CNY | CN China MOQ 25g |
Physicochemical Properties
| Melting Point | 70ºC |
|---|---|
| Boiling Point | 684.9ºC(lit.) |
| Density | 4.81 g/mL at 25ºC(lit.) |
| Flash Point | 690°C |
| Exact Mass | 129.91700 |
| PSA | 57.53000 |
| Appearance | powder |
| Additional Property | H2O: soluble | 167 g/100 mL (20 ºC) |
GHS Safety & Compliance
- H301 — Toxic if swallowed
- H331 — Toxic if inhaled
- H373 — May cause damage to organs through prolonged exposure
- H410 — Very toxic to aquatic life with long lasting effects
Frequently Asked Questions
What is the CAS number of Selenous acid?
The CAS number of Selenous acid is 7783-00-8.
What are the molecular formula and molecular weight of Selenous acid?
Selenous acid has molecular formula H2O3Se and molecular weight 128.97400 g/mol.
Which suppliers offer Selenous acid?
1 supplier(s) listed; reference unit price ¥4.40–14.40 /g.
Is Selenous acid hazardous?
Selenous acid has GHS signal word Danger and hazard statements H301 — Toxic if swallowed; H331 — Toxic if inhaled; H373 — May cause damage to organs through prolonged exposure.
Data compiled from public chemical databases such as PubChem and supplier catalogs; supplier offers are provided by suppliers.
Last updated:
How to cite: Jingsj. "Selenous acid (CAS 7783-00-8)". Jingsj Chemical Database. https://www.jingsj.com/compound/J-47054-0 (accessed 2026-11-06).
Data for reference only; verify product details with suppliers before purchase.