In thermodynamics, the threeple pynt o a substance is the temperatur an pressur at that the three phases (gas, liquid, an solit) o that substance coexeest in thermodynamic equilibrium.[1] For ensaumple, the threeple pynt o mercur occurs at a temperatur o −38.83440 °C an a pressur o 0.2 mPa.


  1. IUPAC, Compendium o Chemical Terminology, 2nt ed. (the "Gold Book") (1997). Online corrected version:  (1994) "Triple point".