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Arsenic trioxide

IUPAC: bis(arsenic(3+));tris(oxygen(2-))

As2O3 Inorganic Compounds CAS 1327-53-3
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Quick Reference
Formula / NotationAs2O3
CAS Number1327-53-3
Molecular Weight197.841
Melting Point379 to 594.1 °F ; Arsenolite and claudetite forms sublime at 379 °F. (EPA, 1998)
Boiling Point869 °F at 760 mmHg (EPA, 1998)
Density3.738 amorphous or vitreous; 3.865 arsenolite; 4.15 claudetite (EPA, 1998)
Solubility17000 mg/L (at 16 °C)
AppearanceArsenic trioxide appears as white or transparent, glassy amorphous lumps or crystalline powder. Slightly soluble in water, but dissolves very slowly; more soluble in hot water. Noncombustible. Corr...
Also Known Asbis(arsenic(3+));tris(oxygen(2-)); Arsenic oxide (As2O3); Arsentrioxide; Arseni trioxydum; Arsenious trioxide; Claudetite; Trixenox; Oxyde Arsenieux; Arsenious Acid Anhydride; Acide arsenieux
CategoryInorganic Compounds

What is Arsenic trioxide?

Arsenic trioxide (As2O3) is an inorganic compound that appears as Arsenic trioxide appears as white or transparent, glassy amorphous lumps or crystalline powder. Slightly soluble in water, but dissolves very slowly; more soluble in hot water. Noncombustible. Corr.... It has a molecular weight of 197.841 g/mol. Its IUPAC name is bis(arsenic(3+));tris(oxygen(2-)). Boiling point: 869 °F at 760 mmHg (EPA, 1998). Melting point: 379 to 594.1 °F ; Arsenolite and claudetite forms sublime at 379 °F. (EPA, 1998).

Formula & Notation

As2O3

IUPAC Name: bis(arsenic(3+));tris(oxygen(2-))

Other Names / Synonyms: bis(arsenic(3+));tris(oxygen(2-)); Arsenic oxide (As2O3); Arsentrioxide; Arseni trioxydum; Arsenious trioxide; Claudetite; Trixenox; Oxyde Arsenieux; Arsenious Acid Anhydride; Acide arsenieux

Properties & Characteristics

Appearance: Arsenic trioxide appears as white or transparent, glassy amorphous lumps or crystalline powder. Slightly soluble in water, but dissolves very slowly; more soluble in hot water. Noncombustible. Corr.... Molecular formula: As2O3. Molecular weight: 197.841 g/mol. Boiling point: 869 °F at 760 mmHg (EPA, 1998). Melting point: 379 to 594.1 °F ; Arsenolite and claudetite forms sublime at 379 °F. (EPA, 1998). Density: 3.738 amorphous or vitreous; 3.865 arsenolite; 4.15 claudetite (EPA, 1998). Solubility: 17000 mg/L (at 16 °C). Vapor pressure: 66.1 mmHg at 593.6 °F (EPA, 1998).

Physical Data

PropertyValue
Melting Point379 to 594.1 °F ; Arsenolite and claudetite forms sublime at 379 °F. (EPA, 1998)
Boiling Point869 °F at 760 mmHg (EPA, 1998)
Density3.738 amorphous or vitreous; 3.865 arsenolite; 4.15 claudetite (EPA, 1998)
Molecular Weight197.841
Solubility17000 mg/L (at 16 °C)
AppearanceArsenic trioxide appears as white or transparent, glassy amorphous lumps or crystalline powder. Slightly soluble in water, but dissolves very slowly; more soluble in hot water. Noncombustible. Corr...

Uses & Applications

Used in industrial processes, materials science, semiconductor manufacture, ceramics, or as a catalyst.

Safety Information

May be corrosive, toxic, or an oxidising agent. Handle in well-ventilated area. Consult SDS before use.

Always consult the SDS/MSDS before handling any chemical. This information is for educational purposes only.

Key Facts

Term Arsenic trioxide
Formula As2O3
CAS Number 1327-53-3
Molecular Weight 197.841
Synonyms bis(arsenic(3+));tris(oxygen(2-)); Arsenic oxide (As2O3); Arsentrioxide; Arseni trioxydum; Arsenious trioxide; Claudetite; Trixenox; Oxyde Arsenieux; Arsenious Acid Anhydride; Acide arsenieux

Frequently Asked Questions

Arsenic trioxide (As2O3) is an inorganic compound that appears as Arsenic trioxide appears as white or transparent, glassy amorphous lumps or crystalline powder. Slightly soluble in water, but dissolves very slowly; more soluble in hot water. Noncombustible. Corr.... It has a molecular weight of 197.841 g/mol. Its IUPAC name is bis(arsenic(3+));tris(oxygen(2-)). Boiling point: 869 °F at 760 mmHg (EPA, 1998). Melting point: 379 to 594.1 °F ; Arsenolite and claudetite forms sublime at 379 °F. (EPA, 1998).

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Editorial standards: Chemical data is sourced from peer-reviewed literature, CAS Registry, NIST WebBook, and PubChem. Safety information reflects guidance from OSHA, ECHA, and IAEA. For educational purposes only — always consult official SDS documentation and qualified professionals before handling chemicals.