Quaternary compound

In chemistry, a quaternary compound is a cation consisting of a central positively charged nitrogen group atom with four substituents, especially organic (alkyl and aryl) groups, discounting hydrogen atoms.[1]

The best known quaternary compounds are quaternary ammonium cations, having a nitrogen atom at the centre.[2] For example, in the following reaction, the nitrogen atom is said to be quaternized as it has gone from 3 to 4 substituents:

\mathrm{R_3N %2B RCl \longrightarrow R_4N^%2B \ Cl^-}

Other examples include substituted phosphonium salts (R4P+), substituted arsonium salts (R4As+) like arsenobetaine, as well as some arsenic containing superconductors.[3] Substituted stibonium (R4Sb+)[4] and bismuthonium salts (R4Bi+) have also been described.[5]

See also

References

  1. ^ IUPAC, Compendium of Chemical Terminology, 2nd ed. (the "Gold Book") (1997). Online corrected version:  (2006–) "Onium compounds".
  2. ^ IUPAC, Compendium of Chemical Terminology, 2nd ed. (the "Gold Book") (1997). Online corrected version:  (2006–) "quaternary ammonium compounds".
  3. ^ Ren, Zhi-An; Yang, Jie; Lu, Wei; Yi, Wei; Shen, Xiao-Li; Li, Zheng-Cai; Che, Guang-Can; Dong, Xiao-Li et al. (2008). "Superconductivity in the iron-based F-doped layered quaternary compound Nd[O1 − x FxFeAs"]. EPL (Europhysics Letters) 82 (5): 57002. Bibcode 2008EL.....8257002R. doi:10.1209/0295-5075/82/57002. http://adsabs.harvard.edu/abs/2008EL.....8257002R.  edit
  4. ^ Widler, H. -J.; Schwarz, W.; Hausen, H. -D.; Weidlein, J. (1977). "Tetramethyl-Arsonium- und -Stibonium-Methylchlorometallate des Galliums und Indiums". Zeitschrift für anorganische und allgemeine Chemie 435: 179. doi:10.1002/zaac.19774350124.  edit
  5. ^ Nicholas C. Norman (1997). Chemistry of arsenic, antimony, and bismuth. Springer Netherlands. p. 316. ISBN 075140389X. http://books.google.at/books?id=vVhpurkfeN4C&pg=PA316&lpg=PA316&dq=tetramethyl+bismuthonium&source=bl&ots=sHfnfzzxWm&sig=e5_UI0j8Ff_W0UDelpUp1zIWsKc&hl=de&ei=FQS3Tp_1DYul-gbqoZWFBg&sa=X&oi=book_result&ct=result&resnum=1&ved=0CB4Q6AEwAA#v=onepage&q=tetramethyl%20bismuthonium&f=false.