Designed these 12 sided dice. Print them using different colours, there are two cation and two anion dice sets. There's a simple set, and another with poly ions and transition metals.

Students can roll the dice, draw the compound, name it, figure out the formula, etc.

Printing:

very standard print, dice are not quite level, you need to level them off in the slicer program you are using. Build on a raft because of the small base. You can resize, I found that about 30mm diameter works well for readability. I printed them at .3mm layers, 3 shells and 10% infill for durability.