Knowles replaced the achiral triphenylphosphine ligands in Wilkinson's catalyst with chiral phosphine ligands. Carbonyl sulfide is a potential alternative fumigant to methyl bromide and phosphine. Commercially available acetylene gas may carry the odors from impurities divinyl sulfide and phosphine. The reaction is catalyzed by phosphine oxides. There are also traces of carbon, ethane, hydrogen sulfide, neon, oxygen, phosphine, and sulfur. Two basic types of chiral phosphine ligands exist. First phosphine imine-forming reaction is conducted involving treatment of the azide with the phosphine. It is also expected to form Rg(I) complexes with ammonia, phosphine, and hydrogen sulfide. Known clastogens include acridine yellow, benzene, ethylene oxide, arsenic, phosphine and mimosine. On contact with water, calcium phosphide releases phosphine, which ignites spontaneously. For example, indium phosphide can be grown with trimethylindium ((CH)In) and phosphine (PH) precursors. These compounds feature tetrahedral phosphorus(V) and are considered relatives of phosphine oxides. This is treated with iodine, triphenyl phosphine, and imidazole to form 2-iodo-3-(2-iodoethyl)-1H-indole. Trace amounts of ammonia, acetylene, ethane, phosphine, and methane have also been detected. The deoxygenation of phosphine oxides has been extensively developed.