Europium(III) oxalate

Europium(III) oxalate (Eu₂(C₂O₄)₃) is a chemical compound of europium and oxalic acid. There are different hydrates including the decahydrate, hexahydrate and tetrahydrate.^[1] Europium(II) oxalate is also known.^[3]

Europium(III) oxalate

Names
IUPAC names Europium(III) oxalate
Other names Europium oxalate Europium trioxalate
Identifiers
CAS Number	3269-12-3 Y
3D model (JSmol)	Interactive image
ChemSpider	144739
ECHA InfoCard	100.019.896
EC Number	221-885-1
PubChem CID	165097
CompTox Dashboard (EPA)	DTXSID80939743
InChI InChI=1S/3C2H2O4.2Eu/c3*3-1(4)2(5)6;;/h3*(H,3,4)(H,5,6);;/q;;;2*+3/p-6 Key: PVDYMOCCGHXJAK-UHFFFAOYSA-H
SMILES C(=O)(C(=O)[O-])[O-].C(=O)(C(=O)[O-])[O-].C(=O)(C(=O)[O-])[O-].[Eu+3].[Eu+3]
Properties
Chemical formula	Eu2(C2O4)3
Molar mass	567.985 g·mol−1 (anhydrous) 640.046 g·mol−1 (tetrahydrate) 676.077 g·mol−1 (hexahydrate) 748.138 g·mol−1 (decahydrate)
Appearance	colourless solid[1]
Solubility in water	1,38 mg·l−1[2]
Hazards
GHS labelling:
Pictograms
Signal word	Danger
Hazard statements	H314, H335
Precautionary statements	P261, P280, P304+P340, P305+P351+P338, P405, P501
Related compounds
Other cations	Cerium(III) oxalate Gadolinium(III) oxalate Holmium(III) oxalate Lanthanum(III) oxalate Neodymium(III) oxalate Praseodymium(III) oxalate Promethium(III) oxalate Samarium(III) oxalate Terbium(III) oxalate Thulium(III) oxalate Ytterbium(III) oxalate
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Preparation

An excess of oxalate is added to a hot solution of Eu³⁺ cations. The resulting precipitate of Eu₂(C₂O₄)₃ ⋅ 10H₂O is dried in a desiccator.^[4]

Properties

Europium(III) oxide (Eu₂O₃) can be prepared by calcining europium(III) oxalate.^[5]

The dehydration of Eu₂(C₂O₄)₃ · 10H₂O occurs below 200 °C:^[1]

Eu₂(C₂O₄)₃·10H₂O → Eu₂(C₂O₄)₃·6H₂O → Eu₂(C₂O₄)₃·4H₂O → Eu₂(C₂O₄)₃

The decomposition of this compound takes place in two stages, the first at 350 °C and the second at about 620 °C.^[1][6]

Eu₂(C₂O₄)₃ → Eu₂[CO₃]₃ + 3 CO → Eu₂O₃ + 3 CO₂ + 3 CO

In the Mössbauer spectrum, Eu₂(C₂O₄)₃ · 10H₂O shows an isomer shift of +0,26 mm/s with a line width of 2,38 mm/s, in reference to EuF₃.^[4][7] The Debye temperature of Eu₂(C₂O₄)₃ is 166±15 K.^[8]

Eu₂(C₂O₄)₃ · 10H₂O crystallizes monoclinically in the space group of P21/c (space group no. 14) with the lattice parameters a = 1098, b = 961, c = 1004 pm and β = 114.2° with four formula units per unit cell.^[9]

Nanoparticles show a line emission when excited by a light source of 393 nm, the transitions ⁵D₀→⁷F₁ (592 nm) and ⁵D₀→⁷F₂ (616 nm) can then be found in the spectrum. This can be used as a red phosphor for white LEDs.^[10]