What is the chemical name of 4H2?

Oh, dude, 4H2 doesn't have a chemical name because it's not a compound or a molecule. It's just a way of saying you have 4 molecules of hydrogen gas (H2). So, like, it's not like you can go around calling it "Tetrahydrogen" or something fancy like that. Just stick with 4H2 and you're good to go!