Cobalt(II) fluoride Cobalt(II) fluoride Cobalt(II) fluoride is a chemical compound with the formula (CoF). It is a pink crystalline solid compound which is antiferromagnetic at low temperatures (T=37.7 K) The formula is given for both the red tetragonal crystal, (CoF), and the tetrahydrate red orthogonal crystal, (CoF·4HO). CoF is used in oxygen-sensitive fields, namely metal production. In low concentrations, it has public health uses. CoF is sparingly soluble in water. The compound can be dissolved in warm mineral acid, and will decompose in boiling water. Yet the hydrate is water-soluble, especially the di-hydrate CoF·2H O and tri-hydrate CoF·3HO forms of the compound.
Chemical element so long (at least 100 million times longer than the estimated age of the universe) that their radioactive decay has yet to be detected by experiment. Elements with atomic numbers 83 through 94 are unstable to the point that their radioactive decay can be detected. Three of these elements, bismuth (element 83), thorium (element 90), and uranium (element 92) have one or more isotopes with half-lives long enough to survive as remnants of the explosive stellar nucleosynthesis that produced the heavy elements before the formation of our solar system. For example, at over 1.9 years, over a billion times longer