Iron(III) phosphate
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IUPAC name Iron(III) phosphate | |
| Other names Ferric orthophosphate, Ferric phosphate | |
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ECHA InfoCard | 100.030.123 |
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| Properties | |
Chemical formula | FePO4 |
| Appearance | yellow-brown solid |
Density | 3.056 g/cm3 (anhydrous) 2.87 g/cm3 (20 °C, dihydrate) |
Melting point | 250 °C (482 °F; 523 K) (dihydrate) decomposes[1] |
Solubility in water | anhydrous: insoluble dihydrate: 0.642 g/100 mL (100 °C)[1] |
Magnetic susceptibility (χ) | +11,500.0·10−6 cm3/mol |
| Thermochemistry | |
Heat capacity (C) | 180.5 J/mol·K (dihydrate)[1] |
Std molar entropy (S | 171.3 J/mol·K (dihydrate)[1] |
Std enthalpy of formation (ΔfH | -1888 kJ/mol (dihydrate)[1] |
| Hazards | |
GHS pictograms |  [2] |
GHS signal word | Warning |
GHS hazard statements | H315, H319, H335[2] |
GHS precautionary statements | P261, P305+351+338[2] |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). | |
Infobox references | |
Iron(III) phosphate, also ferric phosphate,[3][4] is the inorganic compound with the formula FePO4. Several related materials are known, including four polymorphs of FePO4 and two polymorphs of the dihydrate FePO4·(H2O)2. These materials find several technical applications as well as occurring in the mineral kingdom.[5][6]
Contents
1 Structure
2 Uses
2.1 Pesticide
3 Legislation
4 See also
5 References
6 External links
Structure
The most common form of FePO4 adopts the structure of α-quartz. As such the P and Fe have tetrahedral molecular geometry. At high pressures, a phase change occurs to a more dense structure with octahedral Fe centres. Two orthorhombic structures and a monoclinic phase are also known. In the two polymorphs of the dihydrate, the Fe center is octahedral with two mutually cis water ligands.[7]
Uses
Iron(III) phosphate can be used in steel and metal manufacturing processes. When bonded to a metal surface, iron phosphate prevents further oxidation of the metal. Its presence is partially responsible for the corrosion resistance of the Iron pillar of Delhi.
Iron phosphate coatings are also primarily used as base coatings for paint in order to increase adhesion to the iron or steel substrate. It is often used in rustproofing. It can also be used for bonding fabrics, wood, and other materials to these surfaces. Iron phosphate coatings are usually applied as part of a painting or powder coating process.
Anhydrous iron phosphate has been investigated as an intercalation electrode in a lithium-ion battery despite having low electronic conductivity.
Pesticide
Iron phosphate is one of the few molluscicides approved for use in the practice of organic farming.[8]
Pesticide pellets containing iron phosphate plus a chelating agent, such as EDTA, leach heavy metals from soil into groundwater.[9] The Research Institute of Organic Agriculture (FiBL) reported the EDTA content and stated products were likely to be no safer than metaldehyde baits.[10] Ferric phosphate slug and snail baits marketed in the U.S. contain EDTA.[11]
Legislation
Iron(III) phosphate is not allowed as food additive in the European Union. It was withdrawn from the list of allowed substances in the directive 2002/46/EC in 2007.
See also
Iron(II) phosphate, the lower phosphate of iron
Lithium iron phosphate battery, a battery that uses iron phosphate
References
^ abcde "iron(III) phosphate dihydrate". chemister.ru. Retrieved 3 July 2014..mw-parser-output cite.citationfont-style:inherit.mw-parser-output .citation qquotes:"""""""'""'".mw-parser-output .citation .cs1-lock-free abackground:url("//upload.wikimedia.org/wikipedia/commons/thumb/6/65/Lock-green.svg/9px-Lock-green.svg.png")no-repeat;background-position:right .1em center.mw-parser-output .citation .cs1-lock-limited a,.mw-parser-output .citation .cs1-lock-registration abackground:url("//upload.wikimedia.org/wikipedia/commons/thumb/d/d6/Lock-gray-alt-2.svg/9px-Lock-gray-alt-2.svg.png")no-repeat;background-position:right .1em center.mw-parser-output .citation .cs1-lock-subscription abackground:url("//upload.wikimedia.org/wikipedia/commons/thumb/a/aa/Lock-red-alt-2.svg/9px-Lock-red-alt-2.svg.png")no-repeat;background-position:right .1em center.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registrationcolor:#555.mw-parser-output .cs1-subscription span,.mw-parser-output .cs1-registration spanborder-bottom:1px dotted;cursor:help.mw-parser-output .cs1-ws-icon abackground:url("//upload.wikimedia.org/wikipedia/commons/thumb/4/4c/Wikisource-logo.svg/12px-Wikisource-logo.svg.png")no-repeat;background-position:right .1em center.mw-parser-output code.cs1-codecolor:inherit;background:inherit;border:inherit;padding:inherit.mw-parser-output .cs1-hidden-errordisplay:none;font-size:100%.mw-parser-output .cs1-visible-errorfont-size:100%.mw-parser-output .cs1-maintdisplay:none;color:#33aa33;margin-left:0.3em.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration,.mw-parser-output .cs1-formatfont-size:95%.mw-parser-output .cs1-kern-left,.mw-parser-output .cs1-kern-wl-leftpadding-left:0.2em.mw-parser-output .cs1-kern-right,.mw-parser-output .cs1-kern-wl-rightpadding-right:0.2em
^ abc Sigma-Aldrich Co., Iron(III) phosphate dihydrate. Retrieved on 2014-05-03.
^ "Iron(III) Phosphate". NIH, U.S. National Library of Medicine. Retrieved 22 January 2016.
^ "FERRIC PHOSPHATE". EndMemo.com. Retrieved 22 January 2016.
^ Roncal-Herrero, T., Rodriguez-Blanco, J.D., Benning, L.G., Oelkers, E.H. (2009) Precipitation of Iron and Aluminium Phosphates Directly from Aqueous Solution as a Function of Temperature from 50 to 200°C. Crystal Growth & Design, 9, 5197-5205. doi: 10.1021/cg900654m.
^ Song, Y.; Zavalij, P. Y.; Suzuki, M.; Whittingham, M. S. (2002). "New Iron(III) Phosphate Phases: Crystal Structure and Electrochemical and Magnetic Properties" (PDF). Inorganic Chemistry. 41 (22): 5778–5786. doi:10.1021/ic025688q. PMID 12401083. Retrieved 3 July 2014.
^ Zaghib, K.; Julien, C. M. (January 2005). "Structure and electrochemistry of FePO4·2H2O hydrate". Journal of Power Sources. 142: 279–284. doi:10.1016/j.jpowsour.2004.09.042. Retrieved 3 July 2014.
^ "COMMISSION REGULATION (EC) No 889/2008". European Union law. Retrieved 3 July 2014.
^ "The Regional Institute - Slugs, Snails and Iron based Baits: An Increasing Problem and a Low Toxic Specific Action Solution 1". www.regional.org.au. 11 September 2018.
^ http://www2.eduskunta.fi/kerhot/luonto/eurosiili/pdf/FIBL_FeP_Jan06_E.pdf[dead link]
^ "National Organic Standards Board Crops Subcommittee Petitioned Material Proposal Ferric Phosphate (to Remove)" (PDF). August 15, 2012.
External links
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