Dental Amalgam Enables Mercury Chemistry

Laser ablation reactions combining vaporized dental amalgam and oxygen difluoride (OF₂) yield the oxyfluoride compounds OHgF and FOHgF, according to a new report (Angew. Chem. Int. Ed., DOI: 10.1002/anie.201204331). The compounds are the first oxyfluorides observed to incorporate a group 12 metal atom. University of Virginia chemistry professor Lester S. Andrews, who led the work, had previously tried using other sources of mercury to no avail. Then he asked his dentist for samples of standard dental amalgam, 46.5% Hg and 53.5% Permite silver-tin alloy. “We used exactly the same filling material he’s been putting in my mouth,” Andrews says, although Andrews later added more mercury. Theoretical analysis of the products by Sebastian Riedel and Tobias Schlöder of Germany’s University of Freiburg shows that OHgF is a radical Hg(II) compound, with the radical electron located on the oxygen. The mercury in FOHgF is also Hg(II). Other group 12 oxyfluoride compounds might be possible, Andrews says, if researchers can find the right experimental conditions.