According to IUPAC rules, names of chemical elements should not be capitalized. See Wikipedia’s take on the issue:

According to IUPAC, chemical elements are not proper nouns in English; consequently, the full name of an element is not routinely capitalized in English

However, I commonly see people (even in research articles) capitalize the element names, and I wonder why. Is there a historical trend of doing so? Did the rule change at some point? Are element names capitalized in other languages?

  • $\begingroup$ I often wonder about this myself. Some people also capitalize most compound names (including water). However, I'm not reading research articles; I'm reading lab reports. $\endgroup$
    – Ben Norris
    Oct 2, 2013 at 10:52
  • $\begingroup$ @BenNorris it happens it articles, but it's not common (and it would mean the typesetter has done a bad job). It's more common on the internet at large (including many questions on this site) $\endgroup$
    – F'x
    Oct 2, 2013 at 11:12
  • $\begingroup$ Agreed. I would assume the same misunderstanding that leads to capitalization errors for elements and compounds on the internet leads to the same errors in students' work. $\endgroup$
    – Ben Norris
    Oct 2, 2013 at 11:21
  • $\begingroup$ How strange! I worked and taught chemistry (Chemistry) for 20 years, 20 years ago, and have no idea if I capitalized sodium fluoride for example! When I asked students to name NaF was I expecting Sodium Fluoride? It is not in a sentence, so does that matter? $\endgroup$
    – Sam Rybak
    Feb 12, 2021 at 5:31
  • $\begingroup$ Perhaps they recently took biology, and were unconsciously influenced by the initial capitalization of scientific names in binomial nomenclature, e.g., Lepomis cyanellus (green sunfish). $\endgroup$
    – theorist
    Feb 12, 2021 at 5:48

1 Answer 1


This is a Google ngram of the usage of the words: iodine, carbon, nitrogen, zinc and Iodine, Carbon, Nitrogen, Zinc (not at the beginning of the phrase).

There is no historical trend, at least not an usage of an archaic form (we can see that the maximum usage of the capitalized element name is from 1900 to 1960 but normalized to the overall usage is steady). enter image description here

We can make some hypothesis about why someone could choose to write capitalized element names:

  • If we must write element abbreviation capitalized (Zn, Cu, C, N) I can think I have to write the element capitalized even if is not abbreviated.
  • Someone (me too) may think that if I write Zinc it is more unambiguous and means I'm talking about the concept of element "all atoms with the same number of protons in the atomic nucleus" and not about the metal zinc. If you write report with some elemental techniques (XRF, AES) sometimes you feel the urge to specify to the reader (that maybe is not a chemist): "when I write that I've found zinc I mean that in the sample could be present $\ce{Zn}$ but also $\ce{ZnO}$, $\ce{Zn+}$, $\ce{Zn^{2+}}$".
  • The fact the atoms are identical and the definition of a proper noun is: "a noun that in its primary application refers to a unique entity" could induce to think that elements may fit the definition, and so gain the privilege to be capitalized.
  • In alchemy elements such water and fire were capitalized.

enter image description here However up to my knowledge the form not capitalized is preferred even in the others languages, in Italian I'm sure.

  • 1
    $\begingroup$ I wrote an answer on English.SE about capitalization: english.stackexchange.com/questions/329217/…. Since any piece of "gold" has unique properties that identify it as gold and not silver, it isn't a proper noun, just like how any tree that bears apples is an apple tree, not an *Apple Tree. $\endgroup$ Oct 20, 2016 at 19:47
  • 1
    $\begingroup$ The argument about unicity implying being a proper noun is specious. I have only one nose, but that doesn't make it my Nose. $\endgroup$ Oct 29, 2016 at 23:38
  • 1
    $\begingroup$ @DavidRicherby I could argue that your nose is not an unique entity, something that has separate and distinct existence and objective or conceptual reality, but simply but simply a part of an unique entity yourself. But of course is only an hypothesis I am not saying that is the reason... $\endgroup$
    – G M
    Oct 31, 2016 at 14:01
  • $\begingroup$ Which elements are Jupiter and Venus? $\endgroup$
    – user85778
    Dec 14, 2021 at 14:29

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