Re: Symbols for chemical bonds

From: Curtis Clark (
Date: Sun Mar 27 2005 - 10:48:58 CST

  • Next message: Chris Jacobs: "Re: U+0023"

    on 2005-03-27 05:18 Jukka K. Korpela wrote:
    > Which Unicode characters would be most suitable as symbols for chemical
    > bonds? By visual appearance, one might think about using
    > - em dash (or en dash) for single bond
    > - equals sign for double bond
    > - identical to for triple bond
    > - strictly equivalent to for quadruple bond
    > but these would differ quite a lot from the usual semantics of the
    > characters (except for the em dash, which is rather general-purpose
    > anyway). Besides, there would hardly be any guarantee that all the glyphs
    > would be of the same width in a given font.

    Perhaps add to this list MIDDLE DOT for free radical.

    But the semantics of bonding in plain text is not all that
    cut-and-dried. The triple bond in acetylene, H-C≡C-H, is a covalent
    bond, but the triple bond linking cytosine to guanine in DNA, C≡G, is a
    hydrogen bond. The situation seems comparable to the Plane 1 math
    letters: (1) is there a need to maintain semantics of chemical bonds in
    plain text, and (2) is the absence of semantics in the existing corpus a
    source of future ambiguity?

    Much like the apostrophe/glottal stop issue, I can envision a situation
    where IDENTICAL TO and as-yet unencoded TRIPLE COVALENT BOND and TRIPLE
    HYDROGEN BOND would all have the same appearance in a given font. And
    then we would be pointing out how few web pages use them correctly, and
    how H-C≡ is subject to major spoofing.

    Curtis Clark        
    Web Coordinator, Cal Poly Pomona                 +1 909 979 6371
    Professor, Biological Sciences                   +1 909 869 4062

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