Hydrogen compounds are only required to contain carbon. However, most of them also contain hydrogen, and because it is the carbon-hydrogen bond which gives this class of compounds most of its particular chemical characteristics, carbon-hydrogen bonds are required in some definitions of the word "organic" in chemistry. Millions of hydrocarbons are known, and they are usually formed by complicated synthetic pathways that seldom involve elementary hydrogen. Compounds of hydrogen are often called hydrides, a term that is used fairly loosely. The term "hydride" suggests that the H atom has acquired a negative or anionic character, denoted H, and is used when
Compounds of carbon carbonyls: Cr(CO), Co(CO), Fe(CO), Mn(CO), Mo(CO), Ni(CO), W(CO). Important inorganic carbon-sulfur compounds are the carbon sulfides carbon disulfide (CS) and carbonyl sulfide (OCS). Carbon monosulfide (CS) unlike carbon monoxide is very unstable. Important compound classes are thiocarbonates, thiocarbamates, dithiocarbamates and trithiocarbonates. Small inorganic carbon – nitrogen compounds are cyanogen, hydrogen cyanide, cyanamide, isocyanic acid and cyanogen chloride. Paracyanogen is the polymerization product of cyanogen. Cyanuric chloride is the trimer of cyanogen chloride and 2-cyanoguanidine is the dimer of cyanamide. Other types of inorganic compounds include the inorganic salts and complexes of the carbon-containing cyanide, cyanate, fulminate, thiocyanate and cyanamide ions.