The resulting compound, nickel carbonyl, which was described to the Chemical Society in 1890, is both formed and decomposed within a very moderate range of temperature, and on this fact he based a successful process for the extraction of nickel from its ores.
The carbonyl group is not ketonic in character since it yields neither an oxime nor hydrazone.
Compounds containing the group - CH: O are known as aldehydes (q.v.), while the group >C: O (sometimes termed the carbonyl or keto group) characterizes the ketones (q.v.).
By the action of hydroxylamine or phenylhydrazine on aldehydes or ketones, condensation occurs between the carbonyl oxygen of the aldehyde or ketone and the amino group of the hydroxylamine or hydrazine.
This group may be considered as resulting from the fusion of a carbonyl (:CO) and a hydroxyl (HO-) group; and we may expect to meet with compounds bearing structural resemblances to the derivatives of alcohols and aldehydes (or ketones).