Kristallwassers

Kristallwassers is a term used to describe water molecules that are incorporated into the crystal structure of a substance. These water molecules are not merely adsorbed on the surface but are chemically bound within the lattice of the solid. The presence of kristallwassers can significantly influence the physical and chemical properties of a compound, affecting its stability, solubility, melting point, and reactivity.

The amount of kristallwassers present in a compound is often expressed as a stoichiometric ratio, indicating the number of water molecules per formula unit of the substance. For example, a compound with the formula CuSO4·5H2O contains five molecules of kristallwassers for every molecule of copper sulfate. This hydrated form is known as copper sulfate pentahydrate.

When a hydrated compound is heated, the kristallwassers can be released as water vapor, a process known as dehydration. This can lead to a change in the compound's appearance and properties. Conversely, some anhydrous compounds can reabsorb water from the atmosphere to form hydrates, a process called hydration.

The study of kristallwassers is important in various fields, including chemistry, mineralogy, and materials science. Understanding the role of these incorporated water molecules is crucial for controlling and predicting the behavior of many crystalline materials. Examples of substances containing kristallwassers include common salts like gypsum (CaSO4·2H2O) and washing soda (Na2CO3·10H2O).