Caesium tungstate

Caesium tungstate or cesium tungstate is an inorganic chemical compound with the formula Cs₂WO₄.^[2] It is notable for forming a very dense liquid in solution (a solution containing 85.6g Cs₂WO₄ per 100g water has a specific gravity of 3.0133).^[3] The solution is used in diamond processing, since diamond sinks in it, whereas most other rocks float.^[4]

Caesium tungstate

Names
Other names Cesium tungstate Cesium tungsten oxide
Identifiers
CAS Number	13587-19-4
3D model (JSmol)	Interactive image
ChemSpider	11294571
ECHA InfoCard	100.033.639
EC Number	237-019-0
PubChem CID	22269592
CompTox Dashboard (EPA)	DTXSID50890877
InChI InChI=1S/2Cs.4O.W/q2*+1;;;2*-1; Key: VPXSRGLTQINCRV-UHFFFAOYSA-N
SMILES [O-][W](=O)(=O)[O-].[Cs+].[Cs+]
Properties
Chemical formula	Cs2WO4
Molar mass	513.65 g/mol
Melting point	>350 °C[1]
Related compounds
Other cations	Lithium tungstate Sodium tungstate
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Properties

Caesium tungstate forms colorless crystals, which are strongly hygroscopic. A phase transition from orthorhombic to hexagonal crystal system occurs at 536 °C.

Preparation

Caesium tungstate can be obtained by the reaction between caesium chloride (CsCl) and silver tungstate (Ag₂WO₄) or the reaction between tungstic acid and caesium hydroxide.

References

1. Cesium tungstate
2. Perry, Dale L. (2011). Handbook of inorganic compounds (2nd ed.). Boca Raton: CRC Press. ISBN 978-1-4398-1461-1.
3. WO2000036165A2, Young, Tom L.; Bauer, Kathy & Greene, Michael G. et al., "Heavy caesium salt containing liquids for use in separation processes", issued 2000-06-22 
4. US20230114534A1, Cardarelli, Francois, "High Temperature Chemical Process For The Preparation Of Cesium Tungstate", issued 2023-04-13