Your company makes plastic for use in milk jugs and synthetic fleeces using antimony (III) oxide as a catalyst. Looking at recent data, however,
you have found that antimony (III) oxide is possibly carcinogenic (causes
cancer). You would like to replace the antimony with another element.
What elements might bear investigation as replacements and why? (You
can reuse the catalyst in this case, so don't worry about price) (also,
please don't worry about your milk jug being carcinogenic, even if
antimony (III) oxide were used in its production, the company producing it
would be required to ensure it was entirely removed by the FDA before it
could go to consumers)