Zinc phosphate

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Zinc phosphate
Image:Zinc phosphate.jpg
Identifiers
CAS number	[7779-90-0]
Properties
Molecular formula	Zn₃(PO₄)₂
Molar mass	386.11 g/mol
Appearance	white crystals
Density	4 g/cm³, solid
Melting point	900°C
Solubility in water	Insoluble
Structure
Crystal structure	monoclinic
Hazards
EU classification	not listed
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references

Zinc phosphate (Zn₃(P O₄)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). 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^[1]

Zinc phosphate is formed from zinc phosphate cement and used in dentistry. Zinc phosphate cement is one of the oldest and widely used cements, and is commonly used for luting permanent metal 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.