Caesium oxalate

Not to be confused with cerium oxalate.

Caesium oxalate (standard IUPAC spelling), or dicesium oxalate, or cesium oxalate (American spelling) is a chemical compound with the chemical formula Cs₂C₂O₄. It is a caesium salt of oxalic acid. It consists of caesium cations Cs⁺ and oxalate anions C₂O2−4.

Caesium oxalate

Names
IUPAC name Caesium oxalate
Preferred IUPAC name Dicaesium oxalate
Identifiers
CAS Number	1068-63-9 Y
3D model (JSmol)	Interactive image
ChemSpider	10760846
ECHA InfoCard	100.012.683
EC Number	213-950-8
PubChem CID	13628982
UNII	KB9QB78M28 Y
CompTox Dashboard (EPA)	DTXSID401336476
InChI InChI=1S/C2H2O4.2Cs/c3-1(4)2(5)6;;/h(H,3,4)(H,5,6);;/q;2*+1/p-2 Key: HEQUOWMMDQTGCX-UHFFFAOYSA-L
SMILES C(=O)(C(=O)[O-])[O-].[Cs+].[Cs+]
Properties
Chemical formula	Cs2C2O4
Molar mass	353.829 g·mol−1
Appearance	White solid
Solubility in water	76 g/(100 ml) (25 °C)[1]
Hazards
GHS labelling:
Pictograms
Signal word	Warning
Hazard statements	H302, H312
Precautionary statements	P264, P270, P280, P301+P312, P302+P352, P312, P322, P330, P363, P501
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Preparation

Caesium oxalate can be prepared by passing carbon monoxide and carbon dioxide over caesium carbonate at 380 °C:^[2]

Cs₂CO₃ + CO → Cs₂C₂O₄

Other alkali carbonates do not undergo transformation to oxalate.^[2]

Caesium carbonate can react with oxalic acid in aqueous solution to give caesium oxalate.^[3]

Cs₂CO₃ + H₂C₂O₄·2H₂O → Cs₂C₂O₄·H₂O + CO₂ + 2 H₂O

Chemical Reactions

Caesium oxalate can be reduced back into caesium carbonate and carbon monoxide by thermal decomposition.

Cs₂C₂O₄ → Cs₂CO₃ + CO

Double salts

Compounds that contain caesium and another element in addition to the oxalate anion are double salts of caesium and oxalate. The oxalate may form a complex with a metal that can make a salt with caesium.

Examples include:

name	formula	properties	reference
caesium bis(oxalato)oxotitanate(IV) trihydrate	Cs4[TiO(C2O4)2]2·3H2O		[4]
caesium oxalatooxovanadate(IV)	Cs2[VO(C2O4)2]		[5]
caesium tris(oxalato) ferrate(III) dihydrate	Cs3[Fe(C2O4)3]·2H2O		[6]
caesium bis(oxalato) cobaltate(II) tetrahydrate	Cs2[Co(C2O4)2]·4H2O		[7]
caesium bis(oxalato)nickelate(III) tetrahydrate	Cs[Ni(C2O4)2]·4H2O		[8]
caesium tris(oxalato)germanate(IV)	Cs2[Ge(C2O4)3]		[9]
caesium yttrium(III) oxalate monohydrate	CsY(C2O4)2·H2O	monoclinic a = 8.979, b = 6.2299, c = 8.103 Å, β = 90.05° V = 453.3 Å3, space group P2/n	[10]
caesium (diaquo)bis(oxalato)oxoniobate(V) dihydrate	Cs[NbO(C2O4)2(H2O)2]·2H2O		[11]
	Cs2[NH4]2[Mo3O8(C2O4)3]		[12]
tetracaesium dilanthanum(III) oxalate octahydrate	Cs4La2(C2O4)5·8H2O		[13]
tetracaesium dipraseodymium(III) oxalate octahydrate	Cs4Pr2(C2O4)5·8H2O		[13]
caesium neodymium(III) oxalate hexahydrate	CsNd(C2O4)2·6H2O		[13]
caesium samarium(III) oxalate hexahydrate	CsSm(C2O4)2·6H2O		[13]
caesium dysprosium(III) oxalate hydrate	CsDy(C2O4)2·?H2O		[13]
caesium gadolinium(III) oxalate sesquihydrate	CsGd(C2O4)2·1.5H2O		[13]
caesium terbium(III) oxalate sesquihydrate	CsTb(C2O4)2·1.5H2O		[13]
caesium dysprosium(III) oxalate sesquihydrate	CsDy(C2O4)2·1.5H2O		[13]
caesium holmium(III) oxalate sesquihydrate	CsHo(C2O4)2·1.5H2O		[13]
caesium ytterbium(III) oxalate sesquihydrate	CsYb(C2O4)2·1.5H2O		[13]
caesium lutetium(III) oxalate sesquihydrate	CsLu(C2O4)2·1.5H2O		[13]
dicaesium dioxotungsten(VI) oxalate	Cs2[WO2](C2O4)2		[14]
dicaesium dioxotungsten(VI) difluoride monooxalate	Cs2[WO2]F2(C2O4)		[14]
caesium tris(oxalato)rhenate(III)	Cs3[Re(C2O4)3]		[15]
dicaesium uranyl monooxalate monosulfate dihydrate	Cs2[UO2](C2O4)(SO4)·2H2O		[16]
ammonium caesium uranyl monooxalate monosulfate dihydrate	[NH4]Cs[UO2](C2O4)(SO4)·2H2O		[16]
caesium dioxoneptunium(VI) oxalate hydrate	Cs[NpO2]C2O4·nH2O		[17]

Mixed anion compounds containing caesium, oxalate and another anion also exist, such as the uranyl sulfate above, and caesium bis(oxalato)borate (CsBOB) (Cs[B(C₂O₄)₂]).^[18]