New results point to four or more solid forms of hydrogen
Two veterans of high pressure physics, Russell Hemley of the George Washington University in Washington DC and John Tse of the University of Saskatchewan in Canada, and their colleagues have mapped out where crystalline hydrogen at high pressure melts to a liquid when heated.1 And they report spectroscopic evidence for a new high pressure crystal phase which they think might correspond to one previously predicted by quantum calculations – a phase that calculations show to be metallic.