# Species Formula 1965 Phosphorus nitrideNP 1966 HPNHNP 1967 PNHHNP 1968 PNH2 (singlet)H2NP 1969 trans-HPNHH2NP 1970 (CH3)2P=NEtC5H14NP 1971 (CH3)3P=NEtC5H14NP 1972 Trimethylphosphine-N-ethylimineC5H14NP 1973 Hexamethylphosphorous triamideC6H18N3P 1974 Tris(diethylamino)phosphineC12H30N3P 1975 Li(I)N3P (GEDDOI) (Geo) H33LiC21N3P 1976 Phosphorus oxideOP 1977 Phosphorus oxide (Geo)OP 1978 HPOHOP 1979 Trimethylphosphine oxideC3H9OP 1980 Triphenyl phosphine oxide (Geo)C18H15OP 1981 Triphenyl phosphine oxideC18H15OP 1982 Phosphorus dioxideO2P 1983 HPO3HO3P 1984 Methylphosphonic acidCH5O3P 1985 Ethylphosphonic acidC2H7O3P