Praseodymium sulfate octahydrate
|Jmol-3D images||Image 1|
|Molar mass||570.0031 g/mol
714.12534 g/mol (octahydrate)
|Appearance||green crystalline solid|
|Melting point||1010 °C (decomposes)|
|Solubility in water||113.0 g/l (20 °C)
108.8 g/l (25 °C)
|Other anions||Praseodymium carbonate
|Other cations||Neodymium sulfate|
|Related compounds||Praseodymium(III) oxide
|Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)|
|(what is: / ?)|
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.
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. 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.
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.
- National Research Council (U.S.) (1919). Bulletin of the National Research Council. National Academies. pp. 3–. NAP:12020. Retrieved 14 November 2011.
- 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. PDF copy