Copper acetoarsenite
Description
A bright green powder best known as the pigment emerald green (originally called Paris green). Copper acetoarsenite is prepared by reacting sodium arsenite with copper sulfate and acetic acid. First manufactured in 1814, the brilliant green color became popular in Victorian England and Europe where it was used in wallpapers, clothing, artificial flowers, and oil paints. Unfortunately damp rooms caused fungi to react with the arsenic in wallpaper, releasing deadly arsine gas. Both the toxicity and poor color permanency lead to a decline in it use in households as well as artist materials. Currently, copper acetoarsenite is used as a wood preservative, rodenticide, larvicide, and as an antifouling agent in marine paints.
Synonyms and Related Terms
emerald green; Pigment Green 21; CI 77410; verde esmeralda (Esp.); vert cendre (Fr.); acetoarsenito di rame (It.); cupric acetoarsenite; copper acetate arsenite; king's green; Paris green; Schweinfurt green; mineral green; Mitis green; parrot green; Vienna green; new green; patent green; imperial green; Emperor green; Kaiser green; meadow green; mountain green; English green; Sattler green
Risks
- Highly toxic by ingestion, inhalation and skin contact.
- Arsenic compounds are known human carcinogens.
- It does not break down easily, leading to long-term contamination of soil and water supplies
Physical and Chemical Properties
- Soluble in mineral acids, ethanol, potassium cyanide.
- Insoluble in water.
- Decomposes in alkalis.
- Darkens in the presence of sulfur or lead compounds.
- Cu(C2H3O2)2·3Cu(AsO2)2 (mol. wt. = 1013.8 g/mol.)
- CAS = 12002-0308
- Refractive Index = 1.71(alpha); 1.78(beta)
Resources and Citations
- MuseumPests.net: Pesticide Database
- Richard S. Lewis, Hawley's Condensed Chemical Dictionary, Van Nostrand Reinhold, New York, 10th ed., 1993
- The Merck Index, Martha Windholz (ed.), Merck Research Labs, Rahway NJ, 10th edition, 1983 Comment: entry 2692
- Thomas B. Brill, Light Its Interaction with Art and Antiquities, Plenum Press, New York City, 1980
- Wikipedia: Paris green accessed Feb 2026