A chemical expression, reaction, equation, etc. that is set apart within the text. These may be numbered. This is an NLM not an APA element.
((object-id)*, label?, (caption)?, (alt-text | long-desc | ext-link)*, (alternatives | chem-struct | graphic | media | preformat | textual-form)+, (attrib | permissions)*)
The following, in order:
display3.ent