Cobalt ii fluoride tetrahydrate is a water insoluble crystalline substance whose molecular formula is cobalt(II) fluoride. It is a pink crystalline solid that is antiferromagnetic at low temperatures (TN=37.7 K).
The tetrahydrate is not the only form of the compound, it is also found as a di-hydrate and tri-hydrate. It is a weak Lewis acid, but is otherwise quite inert.
The most obvious application for this material is in the production of ferromagnetic alloys. Other major uses include oil refining, etching, and synthetic organic chemistry. It is a good choice for gamma ray detection applications in the nuclear physics community. It is also an important component in the manufacture of high-strength superalloys. The best thing about this compound is that it is readily available in a variety of commercially available formulations, with the cost per unit of volume well within reach of any laboratory budget.