Zinc phosphate

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Zinc phosphate
Zinc phosphate
Names
IUPAC name
Zinc phosphate
Identifiers
7779-90-0 YesY
ChemSpider 22927 YesY
Jmol 3D model Interactive image
PubChem 24519
RTECS number TD0590000
UNII 1E2MCT2M62 YesY
Properties
Zn3(PO4)2
Molar mass 386.11 g/mol
Appearance white crystals
Density 3.998 g/cm3
Melting point 900 °C (1,650 °F; 1,170 K)
insoluble
1.595
Structure
monoclinic
Hazards
NFPA 704
Flammability code 0: Will not burn. E.g., water Health code 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g., chloroform Reactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g., liquid nitrogen Special hazards (white): no codeNFPA 704 four-colored diamond
Flash point Non-flammable
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
YesY verify (what is YesYN ?)
Infobox references

Zinc phosphate (Zn3(PO4)2) is an inorganic chemical compound used as a corrosion resistant coating on metal surfaces either as part of an electroplating process or applied as a primer pigment (see also red lead). It has largely displaced toxic materials based on lead or chromium, and by 2006 it had become the most commonly used corrosion inhibitor.[1] Zinc phosphate coats better on a crystalline structure than bare metal, so a seeding agent is often used as a pre-treatment. One common agent is sodium pyrophosphate.[2]

Natural forms of zinc phosphate include minerals hopeite and parahopeite, Zn3(PO4)2·4H2O. A somewhat similar mineral is natural hydrous zinc phosphate called tarbuttite, Zn2(PO4)(OH). Both are known from oxidation zones of Zn ore beds and were formed through oxidation of sphalerite by the presence of phosphate-rich solutions. The anhydrous form has not yet been found naturally.

Zinc phosphate is formed from zinc phosphate cement and used in dentistry. Zinc phosphate dental cement is one of the oldest and widely used cements, and is commonly used for luting permanent metal and zirconium dioxide[3][4][5][6][7][8] restorations and as a base for dental restorations. Zinc phosphate cement is used for cementation of inlays, crowns, bridges, and orthodontic appliances and occasionally as a temporary restoration. It is prepared by mixing zinc oxide and magnesium oxide powders with a liquid consisting principally of phosphoric acid, water, and buffers. It is the standard cement to measure against. It has the longest track record of use in dentistry. It is still commonly used; however, resin-modified glass ionomer cements are more convenient and stronger when used in a dental setting.

References[edit]

  1. ^ Kalendov´a, A.; Kalenda, P.; Vesel´y, D. (2006). "Comparison of the efficiency of inorganic nonmetal pigments with zinc powder in anticorrosion paints". Progress in Organic Coatings. Elsevier. 57: 1–10. doi:10.1016/j.porgcoat.2006.05.015. 
  2. ^ Menke, Joseph T. "Zinc Phosphate Coatings on NonFerrous Substrates -- Part I". PFOnline. Retrieved 2006-08-07. 
  3. ^ Raab D: Befestigung von Zirkonoxidkeramiken. DENTALZEIZUNG 2007: 6; 32-34. http://www.zwp-online.info/archiv/pub/pim/dz/2007/dz0607/dz607_032_034_hoffmann.pdf
  4. ^ Raab D: Befestigung von Vollkeramiken aus Zirkonoxid. ZAHNARZT WIRTSCHAFT PRAXIS 2007: 12; 98-101. http://www.zwp-online.info/archiv/pub/gim/zwp/2007/zwp1207/zwp1207_098_101_hoffmann.pdf
  5. ^ Raab D: Fixation of all ceramic restorations – the advantages of cementation. DENTAL INC 2008: March / April 50-53.
  6. ^ Raab D: Befestigung von Zirkonoxidkeramiken. ZAHN PRAX 2008: 11; 16-19.
  7. ^ Raab D: Fixation of full ceramic restorations – the advantages of cementation. 全瓷修复的粘接 — 水门汀的优势. DENTAL INC Chinese Edition 2008: Sonderdruck.
  8. ^ Raab D: Konventionelle Befestigung von Vollkeramikrestaurationen. ZAHN PRAX 2009: 12; 84-86.

External links[edit]