Published in Chemistry World, 2 Apr 2012
Researchers in the UK and the US claim to have discovered a new phase of hydrogen in which the diatomic molecules break apart to form six-atom rings, similar to graphene. The new phase, which occurs at very high pressures, could be a stepping stone towards a long-sought after phase: metallic hydrogen.
The quest for metallic hydrogen has been on since the late 19th century, when chemists pointed out that the element, which tops the periodic table’s column of alkali metals, ought to form a metal. In 1935, physicists Eugene Wigner and Hillard Bell Huntington predicted that hydrogen should become a metallic solid at high pressures – roughly 25GPa – but experiments later performed at these pressures showed no trace of a metal transition. More recent experiments have employed higher pressures still. Indeed, last year Mikhail Eremets and Ivan Troyan of the Max-Planck Institute for Chemistry in Mainz, Germany, claimed evidence for metallic hydrogen at pressures up to 260GPa. But other scientists believed that evidence was unreliable. […]
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