Original paper

Phosphatian walpurgite from Smrkovec, the Slavkovsky Les Mts. (the Czech Republic): its description and physico-chemical characteristics

Sejkora, J.; Čejka, J.; Hloušek, J.; Šrein, V.; Novotná , M.

Abstract

Phosphatian walpurgite, (UO2)Bi4O4[(As,P)O4]2 · 2H2O, is triclinic, space group P-1 and a = 7.124(3), b = 10.392(5), c = 5.492(2)Å, α = 101.50(3)°, β = 110.84(3)°, γ = 88.09(4)°, V = 372.1(4)Å3, Z = 1 and Dcalc. = 6.273g/cm3. It forms translucent to cloudy imperfect tabular (flattened on {010}) crystals up to 1mm in length and 50-200μm in width, randomly growing in small fissures and cavities of quartz gangue. It is brittle, pale to wax yellow, it has light grey streak with yellowish tint and adamantine to waxy lustre. Its cleavage is perfect on {010}. Chemical analysis yielded the empirical formula (UO2)0.94(Bi3.77 Ca0.10Cu0.06Fe0.06)Σ3.99 [(AsO4)1.28(PO4)0.81(VO4)0.01(SiO4)0.01]Σ2.11O3.68 · 2.00 H2O. P content in an [(As,P)O4]3- anion varies in the range 23-48mol.%. A detailed interpretation of infrared absorption spectra inclusive calculations U-O (uranyl and equatorial) bond lengths was given. It was found at old mine dumps of an abandoned small ore deposit Smrkovec, 10 km NNE of Mariánské Lázně, western Bohemia, the Czech Republic.

Keywords

walpurgiteuranylx-ray powder datachemical analysisinfrared spectroscopysmrkovecslavkovsky les mtsthe czech republic