Hydrogen turns to a solid at -262 C (11 K). Unfortunately,
the density decreases (sort of like water) from 70.8 g/l to
70.6 g/l.
On compressing hydrogen: (CRC page B-20)
... In 1973 it was reported that a group of Russian experi-
menters may have produced metallic hydrogen at a pressure of
2.8 Mbar. At the transition the density changed from 1.08 g/ml
to 1.3 g/ml. ... It has been predicted that metallic hydrogen
may be metastable; others have predicted it would be a super-
conductor at room temperature. ...
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2.8 Mbar is roughly 2.8 million atmospheres. On the other
hand, 1.08 g/ml is fifteen times denser than liquid H2 at
one atm. Anyone have pressure-volume-temperature charts
for hydrogen?
John H. Kim
[email removed]
[email removed]