Nitrogen tetravalent, compounds containing

V-Bromosuccinimide and similar. V-halo compounds5 oxidize diaryl telluriums to tetravalent tellurium compounds with one halogen atom and the nitrogen-containing group bonded to tellurium. 

The tetravalent, positive ion III has been recognized for some time as it occurs in the ammonium ion +NH4 and in the tetraalkyl ammonium salts (G2H5)4N+I. The other forms are now known to make a contribution to the structures of many nitrogen containing compounds. Thus the following may be considered to be the structures of ammonia,... 

Crystalline addition compounds of alcohols, ethers, aldehydes, and ketones with Bronsted and Lewis acids have been known since the middle of the last century. They were long considered unstable molecular compounds 152 Collie and Tickle153 were the first to assign oxonium salt character to the acid complexes as containing a tetravalent oxygen, analogous to the ammonium salts in which nitrogen at that time was assumed to be pentavalent ... 

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