Kristallivetenä

Kristallivetenä is a Finnish term that translates to "water of crystallization" or "water of hydration" in English. It refers to the molecules of water that are structurally incorporated into the crystal lattice of a solid compound. This water is not merely adsorbed onto the surface of the crystal but is held within the ordered arrangement of atoms or ions that form the crystal.

The presence of kristallivetenä is characteristic of hydrated salts. When a hydrated compound is heated, the water molecules can be released, often leading to a change in the compound's physical properties, such as its color or crystal structure. This process is known as dehydration. Conversely, anhydrous (water-free) compounds can absorb atmospheric moisture to form hydrated crystals, a process called hydration.

The amount of kristallivetenä in a compound is often expressed as a fixed stoichiometric ratio, indicated in the chemical formula. For example, copper(II) sulfate pentahydrate has the formula CuSO4·5H2O, meaning that for every molecule of copper(II) sulfate, there are five molecules of water of crystallization. This water plays a crucial role in stabilizing the crystal structure and can influence the compound's solubility and reactivity. The study of compounds containing kristallivetenä is fundamental in inorganic chemistry and materials science.