High Quality Content by WIKIPEDIA articles! Phosphonites are organophosphorus compounds with the formula P(OR)2R. They are derivivatives of phosphonous acid. Organophosphorus compounds are degradable chemical compounds containing carbon-phosphorus bonds (apart from phosphate and phosphite esters), primarily used in pest control as an alternative to chlorinated hydrocarbons which persist in the environment. Organophosphorus chemistry is the corresponding science of the properties and reactivity of organophosphorus compounds. Phosphorus shares group 5 in the periodic table with nitrogen and phosphorus compounds and nitrogen compounds are somewhat related. The definition of organophosphorus compounds is variable, which can lead to confusion. In industrial and environmental chemistry, an organophosphorus compound need only contain an organic substituent, but need not have a direct P-C bond.