When you add chemistry into a paragraph the Add-In protects its contents by locking the Content Control which is inserted.

A bug exists in Microsoft Word (present in versions 2010, 2013 & 2016) which prevents adujsting of a paragrah’s formattting (such as centering etc) when the first “character” is a locked Content Control. This also applies to table cells and has been reported to the Miscosoft Office Team.

To get around this add a space before inserting a Chemistry object.

Before you import a structure from a file or web service, the add in checks to see if it is valid.

This is an example of an error during the import of a chemical structure from ChEBI:

You may also see a similar dialog when you try to import a structure:

The add in reports an error because the add in does not support an atom found in the import file.  The add in is able to import from many chemistry formats; not all of the atom and bond types that they contain are supported.

The bond-length parameter for each chemistry drawing determines the overall size of the drawing.  To change the size of a chemistry drawing in your Word document, change the bond length using the editor.

First, double-click on the chemistry drawing to open it in the editor.

Next, change the bond length to achieve the desired size of picture in your document.

Click OK to resize the chemical drawing in your Word document..

If you want to change the size of all of the chemistry drawings, you need to repeat this process for each structure.