atom 4dATOM.BIO: The ultimate free tool to unify all your links in one place. Perfect for creators, businesses, and freelancers. Fully customizable – create your4d atomic orbitals. There are five 4d orbitals. These are labelled 4d xy, 4d xz, 4d yz, 4d x 2-y 2 and 4d z 2. The 4d z 2 name is an abbreviation for 3d (3z 2 –r