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ACS: American Chemical Society Citation Style

This guide will show you how to cite your sources using the ACS (American Chemical Society) citation style.

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About ACS Style

Developed by the American Chemical Society, this style may be used for research papers and citing resources in the field of chemistry.

ACS style provides rules for formatting:

  • reporting original research: titles, bylines, affiliations, desciptions of chemical compounds.
  • references included in the body of your essay (in-text)
  • the reference list at the end of your essay (References)

It may seem like citing your sources is tedious, but it's important and there are many reasons to do it.

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 purpose of citing your references is to:

  • identify (cite) other people’s ideas and the information you use within your work
  • avoid plagiarism 
  • allow the reader to find your research sources
  • add credibility to your work

This online guide is based on the ACS  Style Guide, 3rd Edition published in 2006.

Avoiding Plagiarism

 Here are three different ways you can present information you have found in your research to consciously avoid plagiarizing.

1. Direct quote

When you use or copy the exact words or section of words from an author, you can surround that direct quote by quotation marks. Include the correct citation acknowledging the original author in your sentence.

2. Summary

Write a summary using your own words of the ideas or the text you want to use. Be original without using the words of the original work and be sure you cite that statement.

3. Paraphrase

Paraphrasing is similar to a summary. It just means taking what you have read and rewriting it in your own words. You must cite that paraphrase.

ACS 3rd Edition

ACS published a new manual of style in 2006. Many changes were made to reflect the increase in use of electronic materials and publishing formats, such as:

  • the use of Digital Object Identifiers (DOI) in references to print and electronic sources (when available)
  • discussions of markup languages
  • writing style and word usage
  • references to many resources on the internet
  • preparation of figures, tables, and structures
  • conventions in chemistry
  • chemical structures

Writing Centre

Writing Centre

Do you need help writing your paper?  Having some concerns about citation?  Contact the Writing Centre or read their blog and make an appointment with one of their staff to help you.  


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Learn More

ACS Style Guide3rd ed.

QD 8.5 .A25 2006 (Print Book) 


  • Williams Lake Library REFDESK 
  • House of Learning Library, 3rd Floor


ACS Style Guide, 3rd ed., Chapter 14, 2006.