Diamond crystal. Solid carbon comes in different forms known as allotropes depending on the type of chemical bond. The two most common allotropes of pure carbon are diamond and graphite. In graphite the bonds are sp orbital hybrids and the atoms form in planes with each bound to three nearest neighbors 120 degrees apart. In diamond they are sp and the atoms form tetrahedra with each bound to four nearest neighbors. Tetrahedra are rigid, the bonds are strong, and of all known substances diamond has the greatest number of atoms per unit volume, which is why it is both the hardest
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