2o6 ABIOGENIC ORGANIC-CHEMICAL EVOLUTION 



in which an alkyl group has been substituted for one of the 

 hydrogen atoms. 



R\ 



According to N. N. Semenov^"® hydrogen phosphide can 

 be oxidised directly by oxygen, the reaction proceeding by 

 the following stages 



Phosphorous acid is formed in this way and gives rise to 

 the corresponding salts, the phosphites. 



While studying the physico-chemical environment which 

 was formed by the reducing conditions of the primaeval 

 hydrosphere A. Gulick^"^ recently came to the conclusion 

 that its waters must have contained dissolved phosphites 

 rather than orthophosphates, as had been the commonly 

 accepted belief. Under these conditions orthophosphates 

 would have been almost completely insoluble. Gulick points 

 out that even now the amount of phosphorus dissolved in 

 sea water is only 12 parts in 10® by weight. By contrast the 

 solubility of phosphite and hypophosphite (caHPOs and 

 Ca(H2P02)2) in water is comparatively great. These, however, 

 can only persist under reducing conditions. 



Starting from cyanamide (which very probably developed 



