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American Chemical Society (ACS) Style Guide

The ACS citation style was established  by the American Chemical Society. It is recommended for research papers in the field of chemistry. If you are unsure whether this style is required, check with your instructor.

Each citation consists of two parts: the in-text citation, which provides brief identifying information within the text, and the reference list, a list of sources that provides full bibliographic information.

The ACS style requires that you use abbreviated titles for journals. Use the CASSI search tool to find abbreviations for major chemistry journals.

Choose a Format

Before starting your paper, choose one of the following styles:

  • Superscript Numbers
  • Italic Numbers
  • Author Name and Year of Publication

See examples of each style below.

Superscript Numbers

Choose between placing the number at the end of the cited information or within the text of the cited information.

  • Oscillation in the reaction of benzaldehyde with oxygen was reported previously.3 

OR

  • The syntheses described by Fraser3 take advantage of carbohydrate topology.

Italic Numbers

Note that italicized numbers appear in parenthesis. They also can appear at the end of cited text or within the cited text.

  • Oscillation in the reaction of benzaldehyde with oxygen was reported previously (6).
  • Jensen (6) reported oscillation in the reaction of benzaldehyde with oxygen.

Author Name and Year of Publication

Also referred to a the author-date system.

  • Oscillation in the reaction of benzaldehyde with oxygen was reported previously (Finnegan et al., 2004).
  • The primary structure of this enzyme has also been determined (O'Brien and Alenno, 2005; Axelrod, 2003).

Multiple Authors

  • Two authors: provide the surname of both authors, separated by the word "and" (O'Brien and Alenno, 2005).
  • More than two authors: provide the surname of the first author listed, and then "et al." (Finnegan et al., 2004).

Note: This is different from the list of works cited, where all author names should be provided and separated by semicolons.

(Thanks to Trinity College Library)