Quaternary compound explained

In chemistry, a quaternary compound is a compound consisting of exactly four chemical elements.

In another use of the term in organic chemistry, a quaternary compound is or has a cation consisting of a central positively charged atom with four substituents, especially organic (alkyl and aryl) groups, discounting hydrogen atoms.

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

R3N + RCl -> R4N+Cl-

Other examples include substituted phosphonium salts, substituted arsonium salts like arsenobetaine, as well as some arsenic-containing superconductors.^[1] Substituted stibonium ^[2] and bismuthonium salts have also been described.^[3]

See also

• Binary compound
• Ternary compound
• Onium ion
• Quaternary phase

Notes and References

1. Ren . Z. A. . Yang . J. . Lu . W. . Yi . W. . Shen . X. L. . Li . Z. C. . Che . G. C. . Dong . X. L. . Sun . L. L. . Zhou . 10.1209/0295-5075/82/57002 . F. . Zhao . Z. X. . Superconductivity in the iron-based F-doped layered quaternary compound Nd[O1 − x Fx]FeAs . EPL . 82 . 5 . 57002 . 2008 . 2008EL.....8257002R . 0803.4234. 119268175 .
2. Widler . H. -J. . Schwarz . W. . Hausen . H. -D. . Weidlein . J. . Tetramethyl-Arsonium- und -Stibonium-Methylchlorometallate des Galliums und Indiums . 10.1002/zaac.19774350124 . Zeitschrift für anorganische und allgemeine Chemie . 435 . 179–190 . 1977 .
3. Book: Chemistry of arsenic, antimony, and bismuth. Nicholas C. Norman. Springer Netherlands. 1997. 316. 0-7514-0389-X.