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.[1]
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 nα = 1.5399, nβ = 1.5494 and nγ = 1.5607.[1] 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.[3]
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.[3]
References
- ^ a b c d National Research Council (U.S.) (1919). Bulletin of the National Research Council. National Academies. pp. 3–. NAP:12020. Retrieved 14 November 2011.
- ^ "Dipraseodymium trisulphate". pubchem.ncbi.nlm.nih.gov. Retrieved 27 December 2021.
- ^ a b Y.-Q. Zheng, Y.-J. Zhu and J.-L. Lin (2002). "Redeterminaton of the crystal structure of praseodymium sulfate octahydrate, Pr2(SO4)3·8H2O". Zeitschrift für Kristallographie – New Crystal Structures. 217: 299–300. doi:10.1524/ncrs.2002.217.jg.299. S2CID 201278521. PDF copy
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