Liquid ammonia

A breakthrough in chemistry allowed the conversion of a gas, ammonia, into a liquid by lowering the temperature significantly. This development opened up possibilities for refrigeration and becoming a foundational concept in thermodynamics.
 Louis-Bernard Guyton de Morveau France 1798 Liquid ammonia

A breakthrough in chemistry allowed the conversion of a gas, ammonia, into a liquid by lowering the temperature significantly. This development opened up possibilities for refrigeration and becoming a foundational concept in thermodynamics.