Pushing boundaries: first OFZ paper with 300 bar pressure

Our first 300 bar OFZ furnace manufactured for Tyrel McQueen Lab at Johns Hopkins University yielded the first paper, published in the 50th Anniversary Issue of the Journal of Solid State Chemistry (Phelan, W. Adam, et al. “Pushing boundaries: High pressure, supercritical optical floating zone materials discovery.” Journal of Solid State Chemistry 270 (2019): 705-709). The authors describe the potentials of high-pressure atmospheres for the discovery of new materials and report the first successful stable molten zone in an optical furnace at P = 300 bar. At this pressure range, most common gases show a transition to liquids or supercritical fluids, thus the atmosphere is better described as a low density, non-polar, highly polarizable solvent. Concepts from solution-phase chemistry are needed to understand the subtle balance of interactions between the sample and the atmosphere. In this context, the authors report the real-time observation of some poorly understood effects of flow and temperature conditions in the floating zone system. Summarizing they write “High pressure supercritical zone techniques are an expanding frontier in new materials synthesis and discovery. … The authors are particularly excited by the possibility of using the high pressure conditions to expand the range of available materials with unusual anions by combining a pressurized reactive fluid with a traveling solvent.”