Chemix only supports exporting into images. However, with additional tools and specific set up, it is possible to create animations and videos such as these (credits go to https://twitter.com/EfrenR)

How to create animated videos

You will use Chemix to create the individual frames of the video and assemble it using Google Slides. See the 17-minute video below for the full process.

Credits to https://twitter.com/EfrenR for the instructions video.