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I have read two conflicting answers upon a google search:

" 'n' in this context stands for normal or the latin equivalent. That is why, like other Latin and Greek abbreviations, it is in italics. It refers to straight chain alkanes. If we weren't dealing with n-alkanes we would have branched chain isomers to consider and potentially very different answers. It is old nomenclature from the days when adjacent carbons in a molecule were designated alpha,beta,gamma, etc and when acidity was given in 'N' units of normality."

and

" 'n' in science is like "x". It is just a reminder that a number needs to be there. You need to know that numbers can be replaced by x, x/y, n, or any variable and that groups can be replaced by their generic names."

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    $\begingroup$ "n" means a straight chain of carbon atoms. $\endgroup$
    – MaxW
    Sep 23, 2016 at 0:56
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    $\begingroup$ The first one is relevant here - the nomenclature dates to at least 1844 (Gerhardt). From Wikipedia: "Straight-chain alkanes are sometimes indicated by the prefix "n-" (for normal) where a non-linear isomer exists. Although this is not strictly necessary, the usage is still common in cases where there is an important difference in properties between the straight-chain and branched-chain isomers, e.g., n-hexane or 2- or 3-methylpentane." The second one is identifying a generic case where the letter n is used as a variable. $\endgroup$ Sep 23, 2016 at 0:57

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The "n" stands for "normal", which in this context means "straight-chain". It is not italisized, since it is not Latin, but English. In contrast, the prefixes "i" or "a" for "iso" and "anteiso" are Latin and are properly italisized, but rarely are.

Your second choice, "n is like x", can be found in the subscripts of chemical formulae, where it does denote a variable amount.

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  • $\begingroup$ But the n IS italicised for n-alkyldiols. Doesn't that mean it is Latin and not English? And therefore does not mean it is "a straight chain of carbon atoms"? $\endgroup$ Mar 12, 2023 at 1:13

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