Which in-text citation format should I use?

ACS offers three options: superscript numbers¹, italic numbers in parentheses (1), or author-date (Smith, 2024). Choose one and use it consistently throughout your paper. Superscript is most common in chemistry journals.

How do I cite chemical compounds and CAS numbers?

Include CAS Registry Numbers in parentheses after compound names on first mention: aspirin (CAS RN: 50-78-2). For reference works like the CRC Handbook or Merck Index, include the compound name, CAS number, and specific page or entry.

How do I cite a lab manual?

Treat it like a book authored by your instructor and published by your institution: Author. Title of Manual; Institution Name: Location, Year

Do I need to abbreviate journal titles?

Yes. Use Chemical Abstracts Service Source Index (CASSI) abbreviations. You can search for correct abbreviations at cassi.cas.org. Example: Journal of the American Chemical Society becomes J. Am. Chem. Soc.

Yep, include DOIs for all sources that have them. Format as: DOI: 10.xxxx/xxxxx (note the space after the colon). For very recent articles without DOIs, include the database you accessed and the access date.

How to Cite in ACS Format: Complete Chemistry Citation Guide

This guide will help you understand how to properly cite sources in ACS format, the standard citation style for chemistry and biochemistry research, ensuring that your academic work meets the American Chemical Society's guidelines outlined in the ACS Guide to Scholarly Communication.

The Official Source

The ACS Guide to Scholarly Communication (2020) is the current official resource, published online by the American Chemical Society. It supersedes the print ACS Style Guide, 3rd Edition (2006) by Anne M. Coghill and Lorrin R. Garson.

Access the guide at pubs.acs.org/doi/book/10.1021/acsguide.

Quick Overview

ACS uses a numbered citation system with three format options for in-text citations:

Superscript numbers — Most common
Italic numbers in parentheses — Alternative format
Author name with number — When emphasizing the author

References are numbered in the order they first appear in the text.

In-Text Citations

Choose one format and use it consistently throughout your paper.

Superscript Numbers (Most Common)

The reaction mechanism has been well documented.¹
Parker⁴ demonstrated that minimal condensation is expected.

Italic Numbers in Parentheses

The reaction mechanism has been well documented (1).
Chen (9) attributes the slowdown to measurement errors.

Multiple Citations

Several studies support this conclusion.¹⁻³,⁷

Reference List Basics

The reference list is titled "References" and numbered consecutively in citation order.

Basic Structure

#. Author 1; Author 2; Author 3. Title of Article. Journal Abbreviation Year, Volume, Pages. DOI.

Journal Article

Reinke, A. A.; Gestwicki, J. E. Insight into Amyloid Structure Using Chemical Probes. Chem. Biol. Drug Des. 2011, 77, 399–411.

Journal Article with DOI

Lu, H.; Tournet, J.; Dastafkan, K. Noble Metal-Free Electrocatalytic Hydrogen Oxidation. Angew. Chem. Int. Ed. 2021, 60, 14865–14871. DOI: 10.1002/anie.202014679.

Book

Carey, F. A.; Sundberg, R. J. Advanced Organic Chemistry, 5th ed.; Springer: New York, 2007.

Chapter in Book

Asmus, K. D. Recent Aspects of Thiyl and Perthiyl Free Radical Chemistry. In Active Oxygens, Lipid Peroxides, and Antioxidants; Yagi, K., Ed.; Japan Scientific Societies: Tokyo, 1993; pp 57–67.

Website

National Institute of Standards and Technology. NIST Chemistry WebBook. https://webbook.nist.gov/chemistry/ (accessed 2024-01-15).

Patent

Heller, A. Biological Fuel Cell and Methods. U.S. Patent 9,070,934, June 30, 2015.

Key ACS Conventions

Journal abbreviations — Always abbreviate journal names using Chemical Abstracts Service Source Index (CASSI) standards. Search at cassi.cas.org.
Author format — Last name, initials (no periods): Smith, A. B.
Semicolons between authors — Unlike most styles, ACS uses semicolons: Smith, A. B.; Jones, C. D.
Bold year — The publication year is bolded in the reference.
Italic volume — Journal volume numbers are italicized.
No issue numbers — ACS typically omits issue numbers for journals.
DOI format — Include when available: DOI: 10.xxxx/xxxxx
Publisher location — For large publishers (ACS, Wiley, Elsevier, Springer), location is optional.

Common Mistakes to Avoid

Wrong journal abbreviations — Always verify abbreviations in CASSI. "Journal of the American Chemical Society" becomes J. Am. Chem. Soc.
Periods in author initials — Use Smith, A. B. not Smith, A.B. or Smith, A. B..
Commas between authors — Use semicolons, not commas: Smith, A. B.; Jones, C. D.
Missing bold/italics — Year should be bold; volume should be italic.
Alphabetizing references — ACS references are numbered by citation order, not alphabetically.
Including issue numbers — ACS style typically omits issue numbers for journal articles.

Who Uses ACS Style?

ACS is the standard for:

Chemistry journals (especially ACS publications)
Chemical engineering
Biochemistry and molecular biology
Materials science
Pharmaceutical sciences
Environmental chemistry

If you're submitting to an ACS journal or studying chemistry, this is your citation style.

ACS vs. Other Science Styles

Element	ACS	APA	IEEE
In-text format	Superscript or (italic)	(Author, Year)	[#]
Author separator	Semicolon	Comma/&	Semicolon
Year format	Bold	Not bold	Not bold
Journal abbreviation	Required (CASSI)	Optional	Required (IEEE)

Further Resources

ACS Guide to Scholarly Communication — Official online resource
CASSI Search — Journal abbreviation lookup
ACS Author Guidelines — Submission requirements

Wonders can export your sources in ACS format automatically.