Hydroplumboelsmoreite, (Pb₁?₁)_?2(W_1.33Fe³⁺_0.67)_?2O₆(H₂O), a redefined mineral species of the elsmoreite group from China

Abstract Hydroplumboelsmoreite (IMA21-C), (Pb,?) 2 (W,Fe 3+ ) O 6 (H O), is a redefined elsmoreite-group mineral in the pyrochlore supergroup. It was found ‘jixianite’ cotype specimen provided by Mr. Liu Jianchang, who first 1979 Jizhou District, Tianjin City, China. The occurs as yellow to reddish brown aggregates, together with raspite and another under study. cryptocrystalline form occasionally octahedral microcrystalline (under 20 ?m size). crystals are colourless translucent white streak, lustre adamantine greasy. isotropic, calculated refractive index of 2.29, Mohs hardness ~4½–5, density 7.47 g?cm ?3 . strongest five powder X-ray diffraction lines [ d Å( I )( hkl )] 6.070(28)(111), 3.012(100)(222), 2.603(32)(004), 1.836(35)(044) 1.568(30)(226). crystal structure refined R 1 = 0.0459 using 80 unique reflections collected Mo K ? radiation, results show that cubic, space group Fd $\bar{3}$ m , 10.3377(5) Å, V 1104.77(16) Å 3 Z 8. Electron microprobe analyses refinement were used determine empirical formula: (Pb 1.05 Sr 0.05 Ce 0.07 Na 0.01 ? 0.82 ?2.00 (W 1.32 Fe 0.67 Zr [(H O) 0.43 0.19 0.38 ] ?1.00 named hydroplumboelsmoreite based on predominance Pb, W, molecular H A B Y sites, respectively.