efflorescenceThe spontaneous loss of water from a crystalline hydrate, which crumbles on its surface to an anhydrous powder. Sodium carbonate and sulfate are common examples. Like its converse deliquescence, it depends on the relative humidity, occurring if the partial vapor pressure of water at the solid exceeds that of air. Related category PHYSICAL CHEMISTRYAlso on this site: Encyclopedia of Alternative Energy & Sustainable Living Encyclopedia of History |