Mercury dihydride forms a covalent molecular solid
Abstract
Atomic mercury in solid hydrogen reacts when subjected to mercury arc irradiation to form the linear HgH2 molecule with strong IR absorptions at 1902.3 and 772.8 cm−1. Annealing leads to HgH2 dimer and trimer and warming above 7 K allows hydrogen to sublime and solid HgH2 to form. This covalent molecular solid is characterized by strong IR absorptions at 1802, 739 and 673 cm−1 and by decomposition at 150–170 K. Solid para-hydrogen gives sharper HgH2 absorptions at 1905.8 and 774.3 cm−1 and forms a more amorphous HgH2 solid with bands at 1813, 741 and 683 cm−1.