Caesium chromate

Names
IUPAC name

Caesium chromate

Other names

Dicaesium chromate

Identifiers

CAS Number

* 13454-78-9

3D model (JSmol)

* Interactive image

ChemSpider |

* 55521

EC Number |

* 236-640-4

PubChem CID

* 61613

InChI

* InChI=1/Cr.2Cs.4O/q;2*+1;;;2*-1/rCrO4.2Cs/c2-1(3,4)5;;/q-2;2*+1

Key: BROHICCPQMHYFY-UICSPCLAAP

SMILES

* [Cs+].[Cs+].[O-][Cr]([O-])(=O)=O

Properties[1]

Chemical formula

| Cs2CrO4
Appearance  | Yellow crystalline solid
Density | 4.237 g/cm3
Melting point |  954 to 961 °C (1,749 to 1,762 °F; 1,227 to 1,234 K)

Solubility in water

| 45.50 g/100 g (25 °C)
Structure

Crystal structure

| orthorhombic

Space group

| Pnma (№ 62)

Lattice constant

a = 8.368 Å, b = 6.226 Å, c = 11.135 Å

Formula units (Z)

| 4
Hazards
Main hazards | highly toxic, carcinogenic, oxidiser, environmental hazard
GHS pictograms |
GHS Signal word | Danger

GHS hazard statements

| HH272Script error: No such module "Preview warning".Category:GHS errors, HH315Script error: No such module "Preview warning".Category:GHS errors, HH317Script error: No such module "Preview warning".Category:GHS errors, HH319Script error: No such module "Preview warning".Category:GHS errors, HH335Script error: No such module "Preview warning".Category:GHS errors, HH340Script error: No such module "Preview warning".Category:GHS errors, HH350Script error: No such module "Preview warning".Category:GHS errors, HH410Script error: No such module "Preview warning".Category:GHS errors

GHS precautionary statements

| PP203Script error: No such module "Preview warning".Category:GHS errors, PP210Script error: No such module "Preview warning".Category:GHS errors, PP220Script error: No such module "Preview warning".Category:GHS errors, PP261Script error: No such module "Preview warning".Category:GHS errors, PP264Script error: No such module "Preview warning".Category:GHS errors, PP264+P265Script error: No such module "Preview warning".Category:GHS errors, PP271Script error: No such module "Preview warning".Category:GHS errors, PP272Script error: No such module "Preview warning".Category:GHS errors, PP273Script error: No such module "Preview warning".Category:GHS errors, PP280Script error: No such module "Preview warning".Category:GHS errors, PP302+P352Script error: No such module "Preview warning".Category:GHS errors, PP304+P340Script error: No such module "Preview warning".Category:GHS errors, PP305+P351+P338Script error: No such module "Preview warning".Category:GHS errors, PP318Script error: No such module "Preview warning".Category:GHS errors, PP319Script error: No such module "Preview warning".Category:GHS errors, PP321Script error: No such module "Preview warning".Category:GHS errors, PP332+P317Script error: No such module "Preview warning".Category:GHS errors, PP333+P317Script error: No such module "Preview warning".Category:GHS errors, PP337+P317Script error: No such module "Preview warning".Category:GHS errors, PP362+P364Script error: No such module "Preview warning".Category:GHS errors, PP370+P378Script error: No such module "Preview warning".Category:GHS errors, PP391Script error: No such module "Preview warning".Category:GHS errors, PP403+P233Script error: No such module "Preview warning".Category:GHS errors, PP405Script error: No such module "Preview warning".Category:GHS errors, PP501Script error: No such module "Preview warning".Category:GHS errors
Flash point | Non-flammable
Related compounds

Other anions

| Caesium sulfate

Other cations

| Sodium chromate
Potassium chromate
Ammonium chromate

Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Infobox references

Caesium chromate or cesium chromate is an inorganic compound with the formula Cs2CrO4. It is a yellow crystalline solid that is the caesium salt of chromic acid, and it crystallises in the orthorhombic system.

Its major application in the past was for the production of caesium vapour during vacuum tube manufacture.[3] Currently it is only used as the precursor for other compounds of academic interest.[4][5]

## Preparation

Caesium chromate is mainly obtained from the reaction of chromium(VI) oxide with caesium carbonate, wherein carbon dioxide gas is evolved:[4]

CrO3(aq) + Cs2CO3(aq) → Cs2CrO4(aq) + CO2(g)

Alternatively, salt metathesis between potassium chromate and caesium chloride can be performed:[5]

K2CrO4(aq) + 2 CsCl(aq) → Cs2CrO4(aq) + 2 KCl(aq)

Finally, caesium dichromate (itself derived via salt metathesis from ammonium dichromate) yields the chromate following alkalinisation with caesium hydroxide:[3]

Cs2Cr2O7(aq) + 2 CsOH(aq) → 2 Cs2CrO4(aq) + H2O(ℓ)

## Applications

Caesium chromate was formerly used in the final stages of creating vacuum tubes. Therein, caesium vapour was produced by reaction of caesium chromate with silicon, boron, or titanium as reducing agents. The vapour was then added to the tube to react with and remove remaining gases, including nitrogen and oxygen.[6]

## References

1. ↑ Weast, Robert C., ed (1981). CRC Handbook of Chemistry and Physics (62nd ed.). Boca Raton, FL: CRC Press. p. B-91. ISBN 0-8493-0462-8. .
2. ↑ PubChem. "Cesium chromate (Cs2CrO4)" (in en). https://pubchem.ncbi.nlm.nih.gov/compound/61613.
3. ↑ 3.0 3.1 Liebhafsky, H. A.; Winslow, A. F. (1947), "Cesium Chromate Photo-Tube Pellets", Journal of Applied Physics (Journal of Applied Physics, Vol. 18, No. 12) 18 (12): 1128, doi:10.1063/1.1697594, Bibcode: 1947JAP....18.1128L
4. ↑ 4.0 4.1 Pejov, Ljupčo; Petruševski, Vladimir M (2003-08-01). "Latent symmetry versus accidental degeneracy effects in the vibrational spectra of dopant chromate anions in M2CrxS1−xO4 solid solutions (M∈{K, Rb, Cs})" (in en). Journal of Physics and Chemistry of Solids 64 (8): 1353–1363. doi:10.1016/S0022-3697(03)00160-4. ISSN 0022-3697. https://www.sciencedirect.com/science/article/pii/S0022369703001604.
5. ↑ 5.0 5.1 Bender, Johannes; Wohlfarth, Andreas; Hoch, Constantin (2010-12-01). "Crystal Structures of New Alkali Metal-rich Oxometallates: Rubidium Aluminate Tetrahydroxide, Rb9(AlO4)(OH)4, Rubidium Orthogallate, Rb5GaO4, Cesiumbis-Chromate(IV) Oxide, Cs10(CrO4)2O, and Cesium Diindate, Cs8In2O7" (in en). Zeitschrift für Naturforschung B 65 (12): 1416–1426. doi:10.1515/znb-2010-1202. ISSN 1865-7117.
6. ↑ Emsley, John (2001), Nature's Building Blocks: An A-Z Guide to the Elements, Oxford University Press, p. 81, ISBN 0-19-850340-7, https://books.google.com/books?id=j-Xu07p3cKwC&q="Caesium+chromate"+date:1950-2007&pg=RA1-PA81 .

* v
* t
* e

Caesium compounds

* CsBr
* CsCl
* CsClO4
* Cs2CrO4
* CsF
* CsH
* CsI
* CsLiB6O10
* CsNO3
* CsOH
* Cs2CO3
* CsHCO3
* Cs2SO4
* CsC2H3O2
* Cs2O
* Cs2TiO3
* Cs2WO4
* CsAu
* CsHSO4

Template:Chromates and dichromates

0.00

(0 votes)

Original source: https://en.wikipedia.org/wiki/Caesium chromate. Read more

|

Retrieved from "https://handwiki.org/wiki/index.php?title=Chemistry:Caesium_chromate&oldid=4246207"
*[CID]: Compound ID
*[v]: View this template
*[t]: Discuss this template
*[e]: Edit this template