Meltdown of protactinium, rhenium, neon, ruthenium and thulium (double amount) takes time (6,7)
I've triple-checked re: melting and hope I'm ok. I'm sure the chemists, scientists, whateverists will correct me if I'm wrong.
I wanted to use meitnerium (mt) but it seems that there is a lot of guesswork around it as it is unstable. Had to use 'double thulium' (tm).
Go easy now, I'm way out of my depth here!