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Washington, D.C. – Scientists at the Carnegie Institution have discovered a hydrogen-based compound that could be helpful in the search for metallic and superconducting forms of hydrogen.
Metal From Hydrogen- 8/3/2009
Because hydrogen is so light, quantum theory says that it will have a significant energy even when it is cooled to very low temperatures. This is why hydrogen only solidifies at just 14 degrees above absolute zero.
Scientists predicted that it should be possible to form a metal from hydrogen, but the pressure that would be required to do so exceeds that at the center of the earth. By forming compounds of hydrogen with another element like silicon (Si) it is possible to make fairly dense forms of hydrogen that do become metals at more experimentally accessible pressures. In fact, SiH4 becomes a metal at about one tenth of the pressure needed to make pure hydrogen metallic, and a superconductor at about 1 million atmospheres.
In their paper, Timothy Strobel, Maddury Somayazulu, and Russell Hemley present extensive high-pressure experiments on a mixture of SiH4 and H2. At pressures of only about 7.5 GPa, they discovered a new compound, SiH4(H2)2, in which the hydrogen bonds are unusually weak and which may become a metal at higher pressures.
Read the full story at eurekalert.org.