Arsenic trioxide

CAS Registry Number®

No image available.

CAS Name

Arsenic trioxide

Molecular Formula


Cite this Page

Arsenic trioxide.   CAS Common Chemistry.   CAS, a division of the American Chemical Society, n.d. (retrieved 2022-06-29) (CAS RN: 1327-53-3).  Licensed under the Attribution-Noncommercial 4.0 International License (CC BY-NC 4.0).

Compound Properties

  • Boiling Point (1)

    460 °C
  • Melting Point (2)

    275-313 °C
  • Density (2)

    3.7-4.2 g/cm3


  • (1) Hazardous Substances Data Bank data were obtained from the National Library of Medicine (US)
  • (2) International Chemical Safety Cards data were obtained from the National Institute for Occupational Safety and Health (US)

Other Names and Identifiers

Other Names for this Substance

  • Arsenic oxide (As2O3)
  • Arsenic sesquioxide
  • Arsenic trioxide
  • Arsenous oxide
  • White arsenic

Deleted or Replaced CAS Registry Numbers

28380-38-3, 856307-43-2