I don't know of any metal that stays liquid at STP or anywhere around there.
if only they had a thermal paist that is a mix with diamond.
they are only irritants, and extremely poisoneous, just wear gloves and don't swallow , or put it anywhere near your face / wounds. LOL
Also, if I remember correctly Francium and Caesium are both highly reactive. They burn in air and literally explode if they make contact with water.
We could use that in the military weapons, it breaks down other metals, makes them brittle. That would be awesome....