Chemical compounds are substances composed of two or more elements that are chemically bonded together. Oxides are compounds composed of oxygen and another element, such as carbon dioxide. Esters are organic compounds composed of an acid and an alcohol. Enols are a type of organic compound containing a hydroxyl group and a double bond. Dienes are hydrocarbons with two double bonds. Imides are organic compounds containing two carbonyl groups. Imines are organic compounds containing a carbon-nitrogen double bond. Halites are compounds composed of sodium and chlorine. Iodides are compounds composed of iodine and another element. Isomers are compounds with the same molecular formula but different structures.