Zirconium(IV) silicate

Names
Preferred IUPAC name Zirconium(IV) silicate
Systematic IUPAC name Zirconium(4+) silicate
Other names Zircon Zirconium(4+) orthosilicate Zirconium(IV) orthosilicate
Identifiers
CAS Number	10101-52-7 Y
3D model (JSmol)	Interactive image
ChemSpider	55663 N
ECHA InfoCard	100.030.216
EC Number	233-252-7
MeSH	Zircon
PubChem CID	61775
UNII	4SY8H89134 N
CompTox Dashboard (EPA)	DTXSID60892246
InChI InChI=1S/O4Si.Zr/c1-5(2,3)4;/q-4;+4 N Key: GFQYVLUOOAAOGM-UHFFFAOYSA-N N
SMILES [Zr+4].[O-][Si]([O-])([O-])[O-]
Properties
Chemical formula	O4SiZr
Molar mass	183.305 g·mol−1
Appearance	Colourless crystals
Density	4.56 g cm−3
Melting point	1,540 °C (2,800 °F; 1,810 K) (decomposes)
Structure
Crystal structure	tetragonal
Thermochemistry
Heat capacity (C)	98.3 J/mol K
Std enthalpy of formation (ΔfH⦵298)	−2044 kJ/mol
Hazards
NFPA 704 (fire diamond)	1 0 1
Flash point	Non-flammable
Safety data sheet (SDS)	MSDS
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). N verify (what is YN ?) Infobox references

Zirconium silicate, also zirconium orthosilicate, ZrSiO₄, is a chemical compound, a silicate of zirconium. It occurs in nature as zircon, a silicate mineral. Powdered zirconium silicate is also known as zircon flour.

Zirconium silicate is usually colorless, but impurities induce various colorations. It is insoluble in water, acids, alkali and aqua regia. Hardness is 7.5 on the Mohs scale.^[1]

Zircon consists of 8-coordinated Zr⁴⁺ centers linked to tetrahedral orthosilicate SiO₄^4- sites. The oxygen atoms are all triply bridging, each with the environment OZr₂Si. Given its highly crosslinked structure, the material is hard, and hence prized as gemstone and abrasive.

Zr(IV) is a d⁰ ion. Consequently the material is colorless and diamagnetic.

Zirconium silicate occurs in nature as mineral zircon. Concentrated sources of zircon are rare. It is mined from sand deposits and separated by gravity. Some sands contain a few percent of zircon.^[2]

It can also be synthesized by fusion of SiO₂ and ZrO₂ in an arc furnace, or by reacting a zirconium salt with sodium silicate in an aqueous solution.

As of 1995, the annual consumption of zirconium silicate was nearly 1M tons. The major applications exploit its refractory nature and resistance to corrosion by alkali materials.^[2] Two end-uses are for enamels, and ceramic glazes. In enamels and glazes it serves as an opacifier. It can be also present in some cements.

Another use of zirconium silicate is as beads for milling and grinding.

Thin films of zirconium silicate and hafnium silicate produced by chemical vapor deposition, most often MOCVD, can be used as a high-k dielectric as a replacement for silicon dioxide in semiconductors.^[3]

Zirconium silicates have also been studied for potential use in medical applications. For example, ZS-9 is a zirconium silicate that was designed specifically to trap potassium ions over other ions throughout the gastrointestinal tract.^[4]

Zirconium silicate is also used as foundry sands due to its high thermal stability.^[5] t is also the primary source of zirconium, which is used in various applications, including in nuclear reactors, due to its high resistance to corrosion and low neutron absorption.^[6]

Zirconium silicate is an abrasive irritant for skin and eyes. Chronic exposure to dust can cause pulmonary granulomas, skin inflammation, and skin granuloma.^[7] However, there are no known adverse effects for normal, incidental ingestion.^[8]