Chemical element of an element to exist in one of many structural forms is known as 'allotropy'. The standard state, also known as the reference state, of an element is defined as its thermodynamically most stable state at a pressure of 1 bar and a given temperature (typically at 298.15 K). In thermochemistry, an element is defined to have an enthalpy of formation of zero in its standard state. For example, the reference state for carbon is graphite, because the structure of graphite is more stable than that of the other allotropes. Several kinds of descriptive categorizations can be applied broadly to
Diamond Alkali Diamond Alkali Diamond Alkali Company was an American chemical company incorporated in 1910 in West Virginia by a group of glass industry businessmen from Pittsburgh. The company soon established a large chemical plant at Fairport Harbor, Ohio, which would operate for over sixty years. In 1947, the headquarters of the company was moved from Pittsburgh to Cleveland. In 1967, Diamond Alkali and Shamrock Oil and Gas merged to form the Diamond Shamrock Corporation. Diamond Shamrock would go on to merge with Ultramar Corporation, and the combined company, Ultramar Diamond Shamrock Corporation, would in turn be acquired by Valero Energy Corporation