<sub> Subscript

Used to mark text that should appear lower than the baseline and slightly smaller; inferior or subscript text.

Base Attributes

Models and Context
May be contained in
Content Model
<!ELEMENT  sub          (#PCDATA %emphasized-text;)*                 >
Expanded Content Model

(#PCDATA | email | ext-link | uri | inline-supplementary-material | related-article | related-object | bold | fixed-case | italic | monospace | overline | roman | sans-serif | sc | strike | underline | ruby | alternatives | inline-graphic | inline-media | private-char | chem-struct | inline-formula | tex-math | mml:math | abbrev | index-term | index-term-range-end | milestone-end | milestone-start | named-content | styled-content | fn | target | xref | sub | sup)*

Tagged Samples
Expression in text
<fig id="f7" orientation="portrait" position="float">
 <label>FIG. 7.</label>
  <p>(2Si=O-H)<sup>+</sup> complex formation mechanism via three-fold 
   coordination of the O atom with subsequent H 1<italic>s</italic> level 
   lowering and extra electron donation to a DB in SiO<sub>2</sub> and to 
   the Si conduction band in the SiO<sub>2</sub>/Si interface, respectively.
   Electron excitation over to the SiO<sub>2</sub> conduction band denoted 
   by a symbol × is not allowed because the energy needed for excitation over 
   to SiO<sub>2</sub> conduction band is larger than the H 1<italic>s</italic> 
   level lowering.</p>
 <graphic orientation="portrait" position="float" xlink:href="f7"/>
<p>This article by Peter Wilmshurst (10 October 1998, pp 996-9)
 used the incorrect abbreviation for inspired partial pressure of oxygen. 
 The abbreviation should have been Pi<sc>o</sc><sub>2</sub> 
 not Fi<sc>o</sc><sub>2</sub>.</p>
Subscript and superscript “stacked”
As displayed
 <p>The <italic>Escherichia coli argU</italic> gene encodes a minor arginine
  tRNA, tRNA<sup arrange="stack">Arg</sup><sub arrange="stack">UCU</sub>,
  which corresponds to the rare codon AGA and possibly AGG ...</p>