Praseodymium(III) sulfate

Praseodymium(III) sulfate
Praseodymium sulfate octahydrate
Other names Praseodymium sulphate, dipraseodymium trisulphate, praseodymium(III) sulfate
Identifiers
CAS number	13510-41-3 Y,  10277-44-8 (octahydrate)
PubChem	165851,  25022097 (octahydrate)
ChemSpider	145346 N
EC number	233-622-8
Jmol-3D images	Image 1
SMILES [O-]S(=O)(=O)[O-].[O-]S(=O)(=O)[O-].[O-]S(=O)(=O)[O-].[Pr+3].[Pr+3]
InChI InChI=1S/3H2O4S.2Pr/c3*1-5(2,3)4;;/h3*(H2,1,2,3,4);;/q;;;2*+3/p-6 Key: HWZAHTVZMSRSJE-UHFFFAOYSA-H
Properties
Molecular formula	Pr2(SO4)3 Pr2(SO4)3·nH2O, n=2,5,8
Molar mass	570.0031 g/mol 714.12534 g/mol (octahydrate)
Appearance	green crystalline solid
Density	3.72 g/cm3
Melting point	1010 °C (decomposes)
Solubility in water	113.0 g/l (20 °C) 108.8 g/l (25 °C)
Hazards
EU Index	233-622-8
R-phrases	36/37/38
S-phrases	26–36
Main hazards	Xi
Flash point	Non-flammable
Related compounds
Other anions	Praseodymium carbonate Praseodymium chloride
Other cations	Neodymium sulfate
Related compounds	Praseodymium(III) oxide Praseodymium(III) sulfide
N (verify) (what is: Y/N?) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Praseodymium(III) sulfate is a Praseodymium compound with formula Pr₂(SO₄)₃. It is an odourless whitish-green crystalline compound. The anhydrous substance readily absorbs water forming pentahydrate and octahydrate.

Properties

Praseodymium sulfate is stable under standard conditions. At elevated temperatures, it gradually loses water and becomes more whitish. Like all rare earth sulfates, its solubility decreases with temperature, a property once used to separate it from other, non-rare earth compounds.

Pentahydrate and octahydrate have monoclinic crystal structures with densities of 3.713 and 2.813 g/cm³, respectively. The octahydrate crystals are optically biaxial, with refractive index components of n_α = 1.5399, n_β = 1.5494 and n_γ = 1.5607. They belong to the space group C12/c1 (No. 15) and have lattice constants a = 1370.0(2) pm, b = 686.1(1) pm, c = 1845.3(2) pm, β = 102.80(1)° and Z = 4.

Synthesis

Crystals of octahydrate can be grown from solution obtained by dissolving wet Pr₂O₃ powder with sulfuric acid. This procedure can be optimised by adding a few evaporation/dissolution steps involving organic chemicals.