Table C-II Some General Classes of Compound in the Order in which the Characteristic Groups Have Decreasing Priority for Citation as Principal Group

  1. Onium and similar cations (see Subsection C-0.8)
  2. Acids: in the order COOH, C(=O)OOH, then successively their S and Se derivatives, followed by sulfonic, sulfinic acids, etc.
  3. Derivatives of acids: in the order anhydrides, esters, acyl halides, amides, hydrazides, imides, amidines, etc.
  4. Nitriles (cyanides), then isocyanides
  5. Aldehydes, then successively their S and Se analogues; then their derivatives
  6. Ketones, then their analogues and derivatives, in the same order as for aldehydes
  7. Alcohols and phenols; then their S, Se and Te analogues; then neutral esters of alcohols and phenols with inorganic acids, except hydrogen halides, in the same order
  8. Hydroperoxides
  9. Amines; then imines, hydrazines, etc.
  10. Ethers; then successively their S and Se analogues
  11. Peroxides

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