·6H2O definition
·6H2O in its chemical formula means that thomsonite-Ca is a hydrous (or hydrated) mineral with six attached water molecules (H2O). These water molecules are collectively known as “water of hydration.” Consisting of complete, electrically neutral water molecules, water of hydration does not affect the electrical balance of the parent molecule. Water molecules can attach themselves to other molecules because of their unusual atomic configuration, in which two hydrogen ions are grouped together on one side of a large oxygen ion. These grouped hydrogen ions retain a small positive charge, while the opposite side of the water molecule, dominated by the large oxygen ion, retains a small negative charge. This resulting polarity enables water molecules to act as tiny dipole magnets that attach themselves to certain other molecules in a weak attraction called “hydrogen bonding.”