<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
<abbrev>, <addr-line>, <aff>, <alt-title>, <anonymous>, <article-title>, <attrib>, <award-id>, <bold>, <book-title>, <book-volume-id>, <book-volume-number>, <chapter-title>, <chem-struct>, <code>, <collab>, <comment>, <compound-kwd-part>, <compound-subject-part>, <conf-acronym>, <conf-loc>, <conf-name>, <conf-num>, <conf-sponsor>, <conf-theme>, <copyright-holder>, <copyright-statement>, <corresp>, <data-title>, <date-in-citation>, <def-head>, <degrees>, <disp-formula>, <edition>, <element-citation>, <email>, <etal>, <ext-link>, <fax>, <fixed-case>, <funding-source>, <funding-statement>, <given-names>, <gov>, <inline-formula>, <inline-media>, <inline-supplementary-material>, <institution>, <issue>, <issue-part>, <issue-title>, <italic>, <kwd>, <label>, <license-p>, <meta-name>, <meta-value>, <mixed-citation>, <monospace>, <named-content>, <nav-pointer>, <on-behalf-of>, <overline>, <p>, <part-title>, <patent>, <phone>, <prefix>, <preformat>, <product>, <publisher-loc>, <publisher-name>, <rb>, <related-article>, <related-object>, <resource-name>, <role>, <roman>, <sans-serif>, <sc>, <see>, <see-also>, <see-also-entry>, <see-entry>, <self-uri>, <series>, <serif>, <sig>, <sig-block>, <source>, <speaker>, <std>, <std-organization>, <strike>, <string-conf>, <string-date>, <string-name>, <styled-content>, <sub>, <subject>, <subtitle>, <suffix>, <sup>, <supplement>, <support-source>, <surname>, <target>, <td>, <term>, <term-head>, <textual-form>, <th>, <title>, <trans-source>, <trans-subtitle>, <trans-title>, <underline>, <unstructured-kwd-group>, <uri>, <verse-line>, <version>, <volume>, <volume-id>, <volume-number>, <volume-series>, <volume-title>, <x>, <xref>
Any combination of:
Content Model
<!ELEMENT  sub          (#PCDATA %emphasized-text;)*                 >
Expanded Content Model

(#PCDATA | email | ext-link | uri | inline-supplementary-material | related-article | related-object | hr | bold | fixed-case | italic | monospace | overline | overline-start | overline-end | roman | sans-serif | sc | serif | strike | underline | underline-start | underline-end | 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 | x | break)*

Tagged Samples
Inside a caption paragraph
<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>... Apparently, the names of &ldquo;FMR&rdquo; genes
 do not reflect common sequence features but rather 
 a physiological condition, &ldquo;fragile X mental
 retardation&rdquo; syndrome, associated with this gene.
 In this sense, the two are members of a group or family,
 but they show sequence similarity only in the pathological
 trinucleotide repeats (CGG)<sub>n</sub> that are often
 found upstream of their coding regions.</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>