Urea is in equilibrium with cyanate and isocyanate. Urea dissolved in water is in equilibrium with the isomeric ammonium cyanate. Cyanate then hydrolyses to ammonium and carbonate ions. The artificial sweetener dulcin is produced by the condensation of ethoxyaniline with potassium cyanate. It can be prepared by the reaction of potassium cyanate or urea with silver nitrate. The bath is then treated to convert the carbonate back to a cyanate. Functional groups like alkyne, norbornene, maleimide, nitrite, and cyanate have been used for this purpose. A similar reaction is used to make potassium cyanate. The infrared spectrum of a cyanate salt has a band at ca. The cyanate ion is a Lewis base. Sodium cyanate is isostructural with sodium fulminate, confirming the linear structure of the cyanate ion. Remaining free cyanide degrades in the pond, while cyanate ions hydrolyse to ammonium. Potassium cyanate is isostructural with potassium azide. This acetate can be converted to the respective bromide, iodide, cyanate, cyanide, azide and thiocyanate. For example, the Lynx Mark II spaceplane is primarily made of carbon/cyanate ester.