Science, Tech, Math › Science Systematic Chemical Names Systematic and Common Names Print These are crystals of sodium chloride or table salt. Mark Schellhase Science Chemistry Basics Chemical Laws Molecules Periodic Table Projects & Experiments Scientific Method Biochemistry Physical Chemistry Medical Chemistry Chemistry In Everyday Life Famous Chemists Activities for Kids Abbreviations & Acronyms Biology Physics Geology Astronomy Weather & Climate By Anne Marie Helmenstine, Ph.D. Anne Marie Helmenstine, Ph.D. Chemistry Expert Ph.D., Biomedical Sciences, University of Tennessee at Knoxville B.A., Physics and Mathematics, Hastings College Dr. Helmenstine holds a Ph.D. in biomedical sciences and is a science writer, educator, and consultant. She has taught science courses at the high school, college, and graduate levels. Learn about our Editorial Process Updated on August 05, 2018 There are many ways to name a chemical. Here is a look at the difference between different types of chemical names, including systematic names, common names, vernacular names and CAS numbers. Systematic or IUPAC Name The systematic name also called the IUPAC name is the preferred way to name a chemical because each systematic name identifies exactly one chemical. The systematic name is determined by guidelines set forth by the International Union of Pure and Applied Chemistry (IUPAC). Common Name A common name is defined by the IUPAC as a name that unambiguously defines a chemical, yet does not follow the current systematic naming convention. An example of a common name is acetone, which has the systematic name 2-propanone. Read More Chemical Names of Common Substances By Anne Marie Helmenstine, Ph.D. Vernacular Name A vernacular name is a name used in a lab, trade or industry that does not unambiguously describe a single chemical. For example, copper sulfate is a vernacular name which may refer to copper(I) sulfate or copper(II) sulfate. Archaic Name An archaic name is an older name for a chemical that predates the modern naming conventions. It's helpful to know archaic names of chemicals because older texts may refer to chemicals by these names. Some chemicals are sold under archaic names or may be found in storage labeled with the older names. An example of this is muriatic acid, which is the archaic name for hydrochloric acid and is one of the names under which hydrochloric acid is sold. CAS Number A CAS number is an unambiguous identifier assigned to a chemical by the Chemical Abstracts Service (CAS), a part of the American Chemical Society. CAS numbers are assigned sequentially, so you can't tell anything about the chemical by its number. Each CAS number consists of three strings of numbers that are separated by hyphens. The first number contains up to six digits, the second number is two digits, and the third number is a single digit. Other Chemical Identifiers Although the chemical names and CAS Number are the most common way to describe a chemical, there are other chemical identifiers you may encounter. Examples include numbers assigned by PubChem, ChemSpider, UNII, EC number, KEGG, ChEBI, ChEMBL, RTES number and the ATC code. Example of Chemical Names Putting it all together, here are the names for CuSO4·5H2O: Systematic (IUPAC) Name: copper(II) sulfate pentahydrate Common Names: copper(II) sulfate, copper(II) sulfate, cupric sulfate, cupric sulfate Vernacular Name: copper sulfate, copper sulfate Archaic Name: blue vitriol, bluestone, copper vitriol CAS Number: 7758-99-8 Cite this Article Format mla apa chicago Your Citation Helmenstine, Anne Marie, Ph.D. "Systematic Chemical Names." ThoughtCo, Apr. 5, 2023, thoughtco.com/overview-of-chemical-names-608605. Helmenstine, Anne Marie, Ph.D. (2023, April 5). Systematic Chemical Names. Retrieved from https://www.thoughtco.com/overview-of-chemical-names-608605 Helmenstine, Anne Marie, Ph.D. "Systematic Chemical Names." ThoughtCo. https://www.thoughtco.com/overview-of-chemical-names-608605 (accessed April 23, 2024). copy citation