From Mahara Wiki
Chem 2D NIH plugin
This plugin relies on the remarkable Chemical Identifier Resolver service developed by the Computer-Aided Drug Design (CADD) Group of the Chemical Biology Laboratory (CBL), National Cancer Institute (NCI), National Institute of Health (NIH) located at NCI-Frederick.
The Chem 2D NIH (chemnih) plugin returns a Gif image of the 2D structure of any meaningful chemical search term. Valid search terms include a trivial chemical name, systematic (e.g. IUPAC) chemical name, SMILES, InChI or InChIKey. You can set the height and width of the block. You can also select whether the structure is shown in skeletal format (without explicit carbon atom labels or hydrogen atoms) or a fully displayed structure (with all atoms and atom labels).
So, just type in an appropriate term (e.g. ethanol, morphine, buckyball, Cl/C=C\Cl) and you get an (almost) instant image of the 2D structure.
The plugin can be downloaded from Github
On unpackging, the /chemnih folder (and its contents) is simply copied into the /blocktype folder of your Mahara installation
Finally, visit your Site Administration > Plugin Administration page to enable the plugin.