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ACS Style Guide - Citing Your Sources by Emilie Buckley: In-Text Citations

Learn the basics of using ACS format, in-text citations, and supplemental resources. ACS is the style guide for the American Chemical Society.

In-Text Citations

Citing Sources in ACS

When citing your sources in ACS style, choose one of the below options. 

Be consistent!
If you are using superscript numbers, please label them sequentially. If you use a source more than once, go back and use the original number. 
An important rule to remember is: When in doubt, cite your source!

For more detailed information see ACS Style Guide, pp 287-290.

Superscript Numbers

Superscript Numbers


Superscript: The small letter or symbol written above the line of text.

In mathematics, an exponent would be written as a superscript. When using ACS citation style, these small numbers are also used to indicate the citation that is being quoted or paraphrased with an in-text citation. 

How do I use one? 
Place the superscript number outside the punctuation if the citation pertains the entire sentence. 

Helpful hint:
Hit (CNTRL, Shift, +) at the same time as a shortcut to switch to Superscript mode in Word.


Body of Report:

The original experiment called deuterochloroform to dissolve the aspirin product for 1H NMR.2 However, deuterated methanol was used instead due to its superior health and safety profile.3

Works Cited

2) Lehman, J.W. Operational Organic Chemistry: A Problem Solving Approach to the Laboratory.  4th ed.  Pearson Education. 2009. p.144 


3) Methanol-d4. Safety Data Sheet number 151947 [online].  Sigma-aldrich: St. Louis, MO, July 25, 2018.  (accessed June 18, 2019).

Italics in Parentheses

Italics in Parentheses

Add Italicized numbers in parentheses following either:

A) The end of the sentence, before punctuation.

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

B) Following the author's name within the sentence.

Jensen (6) reported oscillation in the reaction of benzaldehyde with oxygen. 

Author Name and Year

Author Name & Year

Similar to APA formatting, one option to citing a source is with the author last name and year of publication. Below are two examples of what this might look like:

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). 

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