64 THE THEORY OF IONS 



oxygen to form sulphone, S0 2 . This is a divalent 

 ion ; when each of its free valencies is united to a 

 carbon atom sulphones are formed ; with a carbon 

 atom to one valency and an OH ion to the other we 

 get sulphonic acid ; with H to one valency and OH 

 to the other we get sulphurous acid ; and with an 

 OH to each valency we get sulphuric acid. 



Sulphonal is an alcohol-derivative of sulphone ; 

 when one of its methyl-radicals is displaced by an 

 ethyl-radical we have trional. Other therapeutic 

 compounds are derived from alcohol, benzene or 

 naphthaline radicals by sulphone or sulphonic acid 

 joining their free valencies, and hydroxyl or OH 

 ions again come into action in some of these 

 replacements. 



Nitrogen, like sulphur, has a variable number of 

 valencies. It can replace the carbon atoms in a 

 closed chain. Among its most important combina- 

 tions are those including oxygen and hydrogen. 



Two atoms of N may unite with two OH ions to 

 form hypo-nitrous acid, N 2 2 H 2 . This is capable of 

 forming salts and ethers. When joining to other 

 compounds, which have only one free valency, it 

 splits into hydroximide, NOH, which is a divalent 

 ion. This again may be robbed of the H atom and 

 remain as Nitrosyl or the NO ion. When two 

 valencies of a carbon atom are available they may 

 be seized by hydroximide or NOH ions. Nitrosyl or 

 NO ions are also capable of entering into direct union 

 with the carbon atom in various compounds. 



One nitrogen atom may also unite with an and 

 an OH ion to form nitrous acid, HN0 2 or NO -OH. 



