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Are Elements Capitalized?

Are Elements Capitalized?

When it comes to being completely clear on when you should and shouldn’t capitalise the names of chemical compounds and their abbreviations, things are not always clear.

Should the word be uppercase or lowercase? Does the capitalization or not of names matter? When should you use a capital letter in a complete sentence? When is a lowercase letter correct to use in the text? The capitalization style is important to get right and in the correct context.

Article titles, for example, may have a capitalized word for each word in the sentence but when used in the main body of the text, things can be different.

If it’s the first word of a sentence, the element or compound name should have the first letter capitalized. Chemical compounds or chemical elements should not be capitalized if they are used in the middle of a sentence.

The associated symbol for it should be capitalized, for example Co for chromium or Co for cobalt.

Read on for more explanation.

Are Chemical Names Capitalized?

Chemical names should not be capitalized with the exception of if they are used as the first word in a sentence. If they are the first word, then it is the first letter of the main section of the word that should be capitalized rather than any prefix that may be present.

For example, in the middle of a sentence you would write sodium nitrate however at the start of the sentence it would be written as Sodium nitrate, with the S capitalised.

Are Chemical Elements Capitalized?

As above, the chemical element name should have the first letter capitalized if it is used as the first word of a sentence. If it’s used in the middle of the sentence, then the chemical element should not be capitalized.

If writing the chemical symbol instead, then the first letter should be capitalized regardless of where it is used in the sentence. For example, the chemical symbol of sodium would always be written as Na.

Are Chemical Formulas Capitalized?

Whilst the chemical compound names are not capitalized within a sentence, chemical formulas should have each of the first letters of their elemental symbols capitalized.

For example, if the chemical formula is used either at the start or middle of a sentence, it would be written as NaNO3.

Are Amino Acids Capitalized?

The full word or name for an amino acid only has the first letter of the word capitalized if it’s used as the first word in a sentence. Anytime an abbreviation is used for an amino acid, then this should be capitalized.

For example, alanine would be written lower case in the middle of a sentence and Alanine at the start of the sentence, with a capitalized A. The abbreviation would be written as Ala regardless of where it’s used in the sentence.


The capitalization and correct use of sentence case of element names can be confusing. If you look at the periodic table, you see the atomic number and all names treated as a proper noun, with the names presented in title case and not lowercase.

As always, the APA style is a good resource to look into for any further clarification.

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