• acid
  • Calcium cyanide can be prepared by treating powdered calcium oxide with boiling anhydrous hydrocyanic acid in the presence of an accelerator such as ammonia or water in order to minimize the loss of the hydrocyanic acid by polymerization. (wikipedia.org)
  • Alternatively calcium cyanide may be prepared by reacting hydrocyanic acid gas with quicklime (CaO) at high temperatures around 400 °C. At higher temperatures around 600 °C calcium cyanimide is formed instead. (wikipedia.org)