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Research Guides

Citing Sources: ACS 3rd ed.

This guide offers resources to help you document the sources you're citing in your research papers and projects.

ACS Style Overview

The ACS (American Chemical Society) citation style is typically used by scholars in the field of Chemistry.

The editors of the ACS Style Guide have chosen to maintain the updates online only - the print guide has not been updated since 2006. Please use the link to the ACS Style Quick Guide to reach open access style examples, as well as other open access materials on Scientific Communication, Scientific Journals, Data in the AI Era, Scientific Style Conventions (this is where you'll find your reference examples), and Editorial Style Conventions. 

How to Format ACS Paper

Basic Formatting

The ACS Style Manual does not supply specific instructions on how to format an ACS document/report, because in publishing, each journal will have its own requirements for formatting. It also does NOT provide guidance on how to format a paper for college assignments. You should consult your instructor for directions on how your paper should be organized and formatted. For more style or citation details, use the online Quick Guide. 

While ACS does not provide guidance on formatting, here are some general guidelines to help you structure your paper. But be sure to check with your instructor to see if they have more specific requirements.

Assignments should be on regular-sized white paper with all margins set to 1-inch and paragraphs set to double-spaced. Footnotes and Endnotes can also be double spaced. Font type and size are not dictated, but should be legible and consistent throughout the paper.

Some recommended styles and sizes include: 12-point Times New Roman, 11-point Calibri, and 11-point Aptos.

In Google Docs: File → Page setup to check that all margins are set at 1".  Format → Line & paragraph spacing to select Double Spaced for the document and set Before and After spacing to zero. Font and font size can be changed in the ribbon menu at the top of the screen.

In Microsoft Word: Layout → Margins → Normal to ensure all margins are set at 1". Paragraph → Spacing → Line spacing dropdown menu, choose Double and set Before and After spacing to zero. Font and font size can be changed in the ribbon menu at the top of the screen.

You can also refer to Preparing a Research Report (link below), a document released in 2015 by ACS with formatting recommendations that you may use for your research paper.

Page Headers

Important! Check with your instructor if they require a running head for your paper. A running head is a shortened version of your paper title or your name printed at the top of every page in the paper EXCEPT on the Title Page. 

If they do NOT, then you only need the page number added to the right side of the header starting with the first page AFTER the Title Page. Your word-processing program will then number each subsequent page.

If they require a running head, it should be flush right in the Header with the page number.

  • For Page Numbers in Google Docs: Insert → Page numbers → Choose More Options. A Page Numbers window will open. Uncheck Show on first page, change the Start at to "0", and hit Apply. Now your second page should be numbered 1.
  • For Running Head in Google Docs: Insert → Headers & footers → Headers. Type in the abbreviated title of your paper or your name and then click your mouse anywhere outside of the header to save it.
  • For Page Numbers and Running Head in Microsoft Word: Insert → Page Number → Top of Page. Select Plain Number 3. In the top menu, select Different First Page so there won't be a number on the Title Page. Again, select Page Number → Format Page Number, and set Start at to 0. Now your second page should be number 1. If you only need page numbers, click on Close Header and Footer, or simply double-click outside the Header to save and close it. If you need to add a running head, place your cursor right in front of the page number and type out the Running Head title for your paper or your name. Hit Tab twice and the title should move to the left of the paper while the page number remains on the right. Click on Close Header and Footer, or simply double-click outside the Header to save and close it.

Title Page

If your instructor requires a Title Page for your paper, it should contain the following elements:

The Title of Your Paper Should Come First: And a Subtitle if You Have One

  • The title should be centered 3 or 4 lines down from the top margin (approx 1/3 way down the paper). It can be the same style and size font as the rest of the paper. Do not make it bold or underline it.
  • About 6-8 spaces down from the title, you should include:

Your Name

Course Code/Number: Course Name

Instructors Name

Date

Paragraph Alignment & Indentation

Paragraphs should be aligned to the left, the right side left uneven (not justified), and the first line of each new paragraph indented by 0.5". Your word-processing program will automatically move words to the next line - do not manually break up or hyphenate a word at the end of a line.

Once you ensure that the paper is left aligned, you can use the tab key to indent at the start of each new paragraph. Or, you can set up your word processing program to automatically indent at the start of each new paragraph when you hit enter.

  • In Google Docs:  Go to Format → Align & Indent → Indentation options → Special indent → Select First line in the dropdown → fill in 0.5 and hit Apply.
  • In Microsoft Word: In the Home tab, click on Paragraph → Indents and Spacing → Indentation → Special: select First line in the dropdown → By: 0.5" → click OK.

Headings

The basic components of most research papers include the following:

  • Title
  • Abstract
  • Introduction
  • Experimental Details or Theoretical Analysis
  • Results
  • Discussion
  • Conclusion and Summary
  • References

If you are using these section headings, they should be Centered on the page. You may also want to bold it, but check with your instructor for further guidance on formatting for headings and subheadings.

References Page

Begin listing your references at the end of your paper on a new page with the heading "References."

References are listed in the order in which they appear in your paper. If the source is used again elsewhere in the paper, the same number should be inserted as the superscript citation for that source.

The reference list should be single spaced. Do not use any type of indentation on citations in your references page that are more than one line. The first line is flush to the left. Put an extra line in between individual references. 

If the same author has more than one reference, put them in order of oldest to newest (i.e. Smith 2001 before Smith 2002).

  • In Google Docs: select your references. Then click on Format → Line and Line Spacing → Single
  • In Microsoft Word: Select your references. Then click Home → Paragraph (Expand w/the arrow) → Line Spacing → Single. 
  • Check with your instructor if you need to add or subtract spacing before or after a line/paragraph.

Examples:


ACS Style: Citing Sources in Text

Why and When to Cite?

Citing or documenting the sources used in your research serves three purposes:

  1. It gives proper credit to the authors of the words or ideas that you incorporated into your paper.
  2. It allows those who are reading your work to locate your sources, in order to learn more about the ideas that you include in your paper.
  3. Citing your sources consistently and accurately helps you avoid committing plagiarism in your writing.

Whenever you paraphrase* or directly quote* something in your paper that comes from an information source found in print, online, or through a personal communication, you need to cite that source at its point of use in your paper. 

In ACS, in-text citations can be formatted in one of two ways:

  • Superscripts at the end of the phrase or sentence.2  This format is generally used with Microsoft Office and other word processing programs, as well as for PDFs and other printed formats. The superscript number comes directly after a word, name, or punctuation with no space.
  • Numbers in parentheses in the sentence (2).  This format is generally used with HTML versions of papers. The parenthetical number comes directly after a word or name with a space in between. However, it comes inside of any punctuation to reduce confusion on what is being cited. 

Note: ACS no longer uses the (Author-Date) format in any of its publications, but it might be used in other journals.

The superscript or parenthetical number corresponds to a complete bibliographic record about the source at the end of your paper in a References list. 

Whether you paraphrase or directly quote a source, superscript or parenthetical citations should be inserted as close as reasonably possible to the information being quoted or paraphrased so that there is no ambiguity as to what information is being cited.

This section goes over how to format your in-text citations. 

It is important to add these in-text citations AS YOU WRITE YOUR PAPER so you do not accidentally plagiarize material by forgetting to do it later.

* Paraphrase - To restate someone else's words or ideas in your own words, often in a more concise or simpler form.
* Direct Quote - To take a statement or written text word for word from someone else and copy it into your text, set apart by quotation marks or in a block quote.
* Superscript - A number in smaller font inserted above and to the right of the last character or punctuation in a clause or sentence to mark the location of a cited source.

In-text Citations

Superscript and Parenthetical citations should be inserted as close as reasonably possible to the information being quoted or paraphrased so that there is no ambiguity as to what information is being cited. This means sometimes your in-text citation will come at the end of a sentence, or it may come at the end of quotations. For more directions and examples, check out ACS's Creating References Guide (see above link).

Direct Quote

Mougios found that CK levels were "statistically higher in athletes that played basketball over soccer players"1 as well as other running sports.

Or

Mougios found that CK levels were "statistically higher in athletes that played basketball over soccer players (1)" as well as other running sports.

Paraphrase

Cancer is best treated through a combination of drugs that often must be administered in a certain order.2

Or

Cancer is best treated through a combination of drugs that often must be administered in a certain order (2).

Multiple Works

* If citation numbers are not in a continuous sequence, separate them with commas. If the numbers are consecutive, use an en dash to connect the first and last number of each continuous sequence.

The research indicated that higher doses did not influence efficacy.2,4,7-10,15 

Or

The research indicated that higher doses did not influence efficacy (2, 4, 7-10, 15).

What if some of the information is missing?

You may come across resources that are missing important pieces of information that would normally go into creating your citation and reference. Here are some things you can do to still correctly cite those items.

No Author?

Check to see if there is a group/organization that can be used as the author. If none or too many organization contributors, skip the author and put the title as the start of the reference. 

No Date?

If no date of publication or copyright year is provided, you can use "n.d." in place of the date where it would be located in the end reference. 

No Publisher?

If a publisher is not listed, you may omit it. Thoroughly check the material to make sure you didn't miss it in the front or back material, or in the "About" information on a website.

How to Format Cited Sources

General Format

  • Title of Article: Article title isn't required, but it's helpful of course for seeing what the article is about.
  • Journal Abbreviation: Use the abbreviation for the journal title and italicize it. Use the CAS Source Index (CASSI) to find the proper abbreviation for the journal you're citing.
  • Volume and Issue: Italicize the volume number. Include the issue number after it in parentheses if each issue starts with page 1 rather than at the page number the last issue left off at.
  • Inclusive Pagination and Article Number: It's acceptable to include just the first page number, but preferable to include the full page range. If it is an online article that doesn't have pagination, include the article number where pagination would be.
  • Indent second and subsequent lines in your list of cited references.

See pages 291-299 of the ACS Style Guide for more guidance and examples.

Print Journal Article

Format

Author, A. B.; Author, C. D., Jr.; Author, E. F. Title of Article. Journal Abbreviation Year, Volume (Issue), Inclusive Pagination.

Example

John, E. R.; Chesler, P.; Bartlett, F.; Victor, I. Observation Learning in Cats. Science 1968, 159 (3822), 1489-1491.

Journal Article from a Library Database

Format

Author, A. B.; Author, C. D., Jr.; Author, E. F. Title of Article. Journal Abbreviation [Online] Year, Volume (Issue), Inclusive Pagination or Article Number. Database Name. URL of database (accessed Month Day, Year).

 * Use the URL of the database rather than of the article.

Example

Maslanka, D. S. Latent Fingerprints on a Nonporous Surface Exposed to Everyday Liquids. J. Forensic Identif [Online]. 2016, 66, 137-154. ProQuest Science Database. https://about.proquest.com/products-services/pq_science_journals.html (accessed June 15, 2020).

Journal Article from Elsewhere Online (i.e. publisher's website)

Format

Author, A. B.; Author, C. D., Jr.; Author, E. F. Title of Article. Journal Abbreviation [Online] Year, Volume (Issue), Inclusive Pagination or Article Number. URL (accessed Month Day, Year).

Example

Chanteau, S. H.; Tour, J. M. Synthesis of Anthropomorphic Molecules: The NanoPutians. J. Org. Chem [Online]. 2003, 68, 8750–8766. https://pubs.acs.org/doi/10.1021/jo0349227 (accessed Jan 14, 2019).

Print News/Magazine Article

Format

Author, A. B.; Author, C. D. Title of Article. Title of Periodical, Month Day, Year, Pagination.

Example

Greenwood, V. How Beets Became Beet-Red. New York Times, Oct 31, 2017, p D2.

News/Magazine Article from a Library Database

Format

Author, A. B.; Author, C. D. Title of Article. Title of Periodical, Month Day, Year, Pagination. Database Name. URL of database (accessed Month Day, Year).

Example

Bastos, E. L. A Blue Dye from Red Beets May Be a Nontoxic Alternative to Colorants with Toxic Metals. Washingtonpost.com, April 17, 2020. Gale General OneFile. https://www.gale.com/c/general-onefile (accessed June 16, 2020).

News/Magazine Article from Elsewhere Online (i.e. publisher's website)

Format

Author, A. B.; Author, C. D. Title of Article. Title of Periodical, Month Day, Year, Pagination. URL (accessed Month Day, Year).

Example

Valsler, B. Beetroot Beats Route to Alzheimer's. Chemistry World, May 2, 2018. https://www.chemistryworld.com/news/beetroot-beats-route-to-alzheimers/3008967.article (accessed June 16, 2020).

Format

Author, A. B. Title of Webpage. URL (accessed Month Day, Year).

At minimum, include:

  • Author, if listed
  • Webpage title
  • URL
  • Date accessed
  • Indent second and subsequent lines

      *See pages 320-321 of the ACS Style Guide for more guidance and examples.

Example

Nitrile to Acid. http://commonorganicchemistry.com/Rxn_Pages/Nitrile_to_Acid/ Nitrile_to_Acid_Index.htm (accessed July 2, 2018).