In the earth's crust fluoride is a relatively common element with 525 ppm. It is because of its reactivity in nature not elementary but bound as fluoride in the form of some minerals before. An exception is Stinkspat (one containing uranium fluorite variety) u. A. From Wölsendorf arise in which small amounts of fluorine by radiolysis what a strong odor caused by released fluorine in mechanical machining. Seawater contains little dissolved fluorides, which have only a very low solubility in water. The most common fluorine minerals are of fluorite CaF2 and the fluoroapatite Ca 5 (PO 4) 3F. Most of the fluorite is bound in fluorapatite, but it contains only a small mass fraction of 3.5% fluorine. Therefore fluorapatite is not degraded due to its fluorine content, but primarily as a source of phosphate. The main source for the recovery of fluorine and fluorine compounds is of fluorite. Larger fluorite exist in Mexico, China, South Africa, Spain undRussland. is also found in Germany, such as Wölsendorf in Upper Palatinate fluorite.
Although fluoride is too reactive to have a natural biological function , it incorporate itself in the biological activity . Natural organic fluorine compounds are rare , the most notable example is fluoroacetate , which as a defense against herbivores plants in at least 40 plants in Australia , Brazil and África.8 functions The adenosylme- fluoride synthase catalyzes the formation of 5'- deoxy fluoroadenosine -5' . Fluoride is not an essential nutrient , but the topical application in the prevention of dental caries is well known. The effect is , topical ( application to the enamel surface ) , but after 1981 it was systemic primarily (oral ) 0.9 The systemic use is now considered by many authors and less discouraged controversial.