ABSTRACT
Phosphorus is a very reactive element and does not occur in a free state in nature. It is typically found in combinations with oxygen, as phosphate, at the redox state 132+5. Phosphorus makes up 0.09% by mass of the Earth’s crust and, with this, it is the 14th most abundant element on Earth. The most important natural phosphate minerals are calcium phosphates such as apatite Ca5(PO4)3(OH,F,Cl) and, as a sedimentary derivative of apatites and of organic matter of biological origin, phosphorite Ca3(PO4)2. To a minor degree, also iron and aluminum phosphates are found, e.g., vivianite, Fe3(PO4)2 · 8 H2O and wavellite Al3(PO4)2(OH,F)3 · 5 H2O [1]. Phosphorus makes up ~2–3% of dry biomass and is especially enriched in animal bones (up to 10%). Actually, the first preparation of pure phosphorus by the alchemist Hennig Brandt in Hamburg in 1669 started from biological material, i.e., urine, which was condensed and heated, leading to a reductive transformation of NaNH4HPO4 by organic matter to white phosphorus which glows in the dark and gave this element its name (Greek phosphoros = light carrier). The history of phosphorus discovery and its utilization by mankind, among others in the production of matches and of firebombs (attributing to it its surname “the Devil’s element”), has recently been described in detail in a shocking novel [2].
