Defying a 150-year-old rule for phase behaviorFrozen water can take on up to three forms at the same
Defying a 150-year-old rule for phase behavior
Frozen water can take on up to three forms at the same time when it melts: liquid, ice and gas. This principle, which states that many substances can occur in up to three phases simultaneously, was explained 150 years ago by the Gibbs phase rule. Today, researchers from Eindhoven University of Technology and University Paris-Saclay are defying this classical theory, with proof of a five-phase equilibrium, something that many scholars considered impossible. This new knowledge yields useful insights for industries that work with complex mixtures, such as in the production of mayonnaise, paint or LCDs. The researchers have published their results in the journal Physical Review Letters.
The founder of contemporary thermodynamics and physical chemistry is the American physicist Josiah Willard Gibbs. In the 1870s, he derived the phase rule, which describes the maximum number of different phases a substance or mixture of substances can assume simultaneously. For pure substances, the Gibbs Phase Rule predicts a maximum of three phases.
Professor Remco Tuinier, of the Institute for Complex Molecular Systems, says, “At the time, Einstein called Gibbs’ thermodynamics the only theory he really trusted. If we take water as an example, there is one point, with a specific temperature and pressure, where water occurs as gas, liquid and ice at the same time, the so-called triple point.”
