Surf Wiki
Save to docs
general/cyanides

From Surf Wiki (app.surf) — the open knowledge base

Calcium cyanide

Highly Toxic | NFPA-H = 3 | NFPA-F = 0 | NFPA-R = 1 | NFPA-S = Calcium cyanide is the inorganic compound with the formula Ca(CN)2. It is the calcium salt derived from hydrocyanic acid. It is a white solid, although the pure material is rarely encountered. It slowly hydrolyses in solution or moist air to release hydrogen cyanide and is very toxic.

Preparation

Solutions of calcium cyanide can be prepared by treating calcium hydroxide with hydrogen cyanide. Solid calcium cyanide is produced commercially by heating calcium cyanamide with sodium chloride. The reaction is incomplete. The product is only of 50% purity, other components being sodium cyanide, calcium cyanamide, and carbon. Because of the carbon impurity, the solid is black, hence material is often called black cyanide.

Reactivity

At temperatures around 600 °C, calcium cyanide converts to calcium cyanamide: :Ca(CN)2 → CaCN2 + C It is suspected that this reaction is one step in the conversion of calcium carbide with nitrogen gas. The ratio of calcium cyanide to calcium cyanamide is sensitive to the presence of alkali metal halides, such as sodium chloride.

Calcium cyanide hydrolyzes upon acidification to form hydrogen cyanide: :Ca(CN)2 + 2H+ → Ca2+ + 2HCN Calcium cyanide reacts with ammonium carbonate to give produce ammonium cyanide: :Ca(CN)2 + (NH4)2CO3 → 2NH4CN + CaCO3

Uses

Main article: Gold cyanidation

Calcium cyanide is used almost exclusively in the mining industry. It serves as an inexpensive source of cyanide in many leaching or vat operation to obtain precious metals such as gold and silver from their ores.

Safety

Main article: cyanide poisoning

Like other cyanide salts, this compound is highly toxic and its use is strictly regulated.

References

References

  1. "GESTIS-Stoffdatenbank".
  2. "CALCIUM CYANIDE | CAMEO Chemicals | NOAA".
  3. (2004). "Cyano Compounds, Inorganic".
  4. "Production of Hydrocyanic Acid" ''United States Patent Office.'' '''1933'''.(accessed April 22, 2012).
  5. Thomas Güthner. (2006). "Cyanamides". [[Wiley-VCH]].
  6. link. (2012-02-29 (accessed April 22, 2012).)
Info: Wikipedia Source

This article was imported from Wikipedia and is available under the Creative Commons Attribution-ShareAlike 4.0 License. Content has been adapted to SurfDoc format. Original contributors can be found on the article history page.

cyanides calcium-compounds gold-mining
Want to explore this topic further?

Ask Mako anything about Calcium cyanide — get instant answers, deeper analysis, and related topics.

Research with Mako

Free with your Surf account

Content sourced from Wikipedia, available under CC BY-SA 4.0.

This content may have been generated or modified by AI. CloudSurf Software LLC is not responsible for the accuracy, completeness, or reliability of AI-generated content. Always verify important information from primary sources.

Report