refrigerant
A substance used in a thermodynamic heat pump cycle or refrigeration cycle that undergoes a phase change from a gas to a liquid and back. Refrigerants are used in air-conditioning systems and freezers or refrigerators and are assigned a "R" number (by ASHRAE - formerly the American Society of Heating, Refrigerating and Air Conditioning Engineers), which is determined systematically according to their molecular structure.
NMR chemical shift reference compound
Any compound that produces a peak used as reference frequency in the delta chemical shift scale.
NMR solvent
A solvent used in nuclear magnetic resonance (NMR) spectroscopy.
|