Phosphorus occurrence

Phosphorus occurrence in the lithosphere is predominantly as phosphates, P04 , although a rare iron-nickel phosphide, schreibersite ((Fe, Ni)3P)g is also known in nature [1]. For this reason, phosphates are the primary source of elemental phosphorus for chemical process requirements. Only 0.20-0.27% phosphate (0.15-0.20% as P2O5 0.07-0.09% as P) is present in ordinary crustal rocks. 

Studies involving phosphmis compounds adsorbed on activated carbons Measurements on coals and related matmals Studies of phosphorus occurrence in soil matter, peat, and related materials Studies of surface properties of porous carbons, coals, carbon nanotubes, and other carbon materials using NMR measurements on adsorbed xenon... 

Some elements contain a fixed number of neutrons, as with fluorine (P = 9, N = 10) and phosphorus (P = 15, N = 16). For their natural occurrences, atoms of any one such element all have the same mass (F= 19 P = 31). 

Phosphorus [7723-14-0] is a nonmetaUic element having widespread occurrence in nature as phosphate compounds (see Phosphoric acid and phosphates). Fluorapatite [1306-03-4], Ca F(P0 2> is the primary mineral in phosphate rock ores from which useful phosphoms compounds (qv) ate produced. The recovery from the ore into commercial chemicals is accompHshed by two routes the electric furnace process, which yields elemental phosphoms and the wet acid process, which generates phosphoric acid. The former is discussed herein (see Furnaces, electric). Less than 10% of the phosphate rock mined in the world is processed in electric furnaces. Over 90% is processed by the wet process, used primarily to make fertilisers (qv). 

Phosphorous acid, 372 Phosphorus black, 365 boiling point, 374 chemistry of, 368 compounds, 102 heat of vaporization, 374 ionization energy, 268 melting point, 374 occurrence, 373 oxyacids, 371, 372 preparation, 374, 376 properties, 101 structure, 366 white, 120, 365, 366, 369 Photon, 254... 

The last reaction is the most favored of these three. The actual occurrence of the reactions with elemental phosphorus or phosphorous trichloride as products has been explained to be due to kinetic reasons. The thorium present in the ore volatilizes in the form of thorium tetrachloride (ThCl4) vapor other metallic impurities such as iron, chromium, aluminum, and titanium also form chlorides and vaporize. The product obtained after chlorination at 900 °C is virtually free from thorium chloride and phosphorous compounds, and also from the metals iron, aluminum, chromium, and titanium. 

Nonpharmacologic Therapy Pruritus associated with CKD is difficult to alleviate. It is important to evaluate other potential dermatologic causes of pruritus to maximize the potential for relief. Adequate dialysis is generally the first line of treatment in patients with pruritus. However, this has not been shown to decrease the incidence of pruritus significantly. Maintaining proper nutritional intake, especially with regard to dietary phosphorus and protein intake, may lessen the degree or occurrence of pruritus. Patients who do not attain relief from other measures may benefit from ultraviolet B phototherapy. 

Noteworthy NMR studies involving nuclei other than phosphorus have been carried out for some P-chloro-NHPs where the possible occurrence of spontaneous P-Cl bond dissociation was probed by II NMR titrations and 35C1 NMR [20], and for P-cyclopentadienyl derivatives where measurement of solid-state 13C CP-MAS NMR spectra allowed one to substantiate the preservation of the circumambulatory ring migration of cyclopentadienyl groups in the solid state [47], Several neutral and cationic derivatives have also been studied by 15N NMR [20, 53],... 

For example, in the instance of 9-chloroacridine, the attachment of the halogen (leaving group) at a suitably electrophilic carbon site allows the occurrence of a replacement reaction, presumably occurring via an addition-elimination procedure for phosphorus attachment, followed by the common nucleophilic displacement (ester cleavage) of the Michaelis-Arbuzov process (Figure 6.1).4... 

The controlled occurrence of two electrophilic aromatic substitution reactions at a single phosphorus center using phosphorus trichloride has been accomplished using aluminum chloride as the catalyst, but with tris(2-chloroethyl) phosphite as the agent for the decomposition of the adduct-Lewis acid complex (Figure 6.13).60... 

Occurrence. Widely distributed in many minerals (more than 200 minerals are known). Commercial sources of phosphorus are apatites (for instance fluoroapatite [3Ca3(P04)2 Ca(F,Cl)2]). 

Regnery J, Puttmann W, Merz, C, Berthold G (2011) Occurrence and distribution of organo-phosphorus flame retardants and plasticizers in anthropogenically affected groundwater. J Environ Monit 13 347-354... 

This circular reviews the occurrence of 34 trace elements in coal and the occurrence and distribution of chlorine, phosphorus, titanium, and manganese, which are not considered rare in coal. Separate chapters are devoted to germanium, gallium, and uranium in coal. 

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