Novel Pressure-Induced Interactions in Silane-Hydrogen

We report novel molecular compound formation from silane-hydrogen mixtures with intermolecular interactions unprecedented for hydrogen-rich solids. A complex H(2) vibron spectrum with anticorrelated pressure-frequency dependencies and a striking H-D exchange below 10 GPa reveal strong and unusual attractive interactions between SiH(4) and H(2) and molecular bond destabilization at remarkably low pressure. The unique features of the observed SiH(4)(H(2))(2) compound suggest a new range of accessible pressure-driven intermolecular interactions for hydrogen-bearing simple molecular systems and a new approach to perturb the hydrogen covalent bond.