Crystal Chemistry of Thallium in Marine Ferromanganese Deposits

Abstract

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Fossil Bioapatites with Extremely High Concentrations of Rare Earth Elements and Yttrium from Deep-Sea Pelagic Sediments

“…Ce L 3 -edge XANES spectra. (a) Spectra of Ce­(III)­NO 3 ·6H 2 O and a hydrogenetic crust (D20-1B) as reference for Ce­(IV)-MnO 2 measured at normal resolution with an energy-dispersive detector (EDD) and at high energy-resolution (HR-XANES) with a crystal-analyzer spectrometer (CAS) . (b) Hydrogenetic crust D20-1B and CeO 2 at normal and high resolution.…”

“…Thanks to its enhanced sensitivity and resolution, Ce L 3 -edge HR-XANES appears to be the most straightforward and reliable way to assess the oxidation state of Ce and the identity of the Ce phase in earth materials. Besides Ce, this technique has been used previously for the distinction of the As­(-I)/As­(III)/As­(V), , Se­(-I)/Se­(IV)/Se­(VI), Eu­(II)/Eu­(III), Au(0)/Au­(I)/Au­(III), − Tl­(I)/Tl­(III), U­(IV)/U­(V)/U­(VI), , and Hg(0)/Hg­(II) , oxidation states.…”

“…The Ce L 3 -edge HR-XANES spectra of single apatite grains and pressed pellets of the bulk sediments were measured at the French CRG FAME-UHD (BM16) beamline of the European Synchrotron Radiation Facility (ESRF) together with the following references: the Durango apatite from Gerin et al (2017) (Ce­(III)), Ce­(NO 3 ) 3 ·6H 2 O (Ce­(III)), cerianite (Ce­(IV)­O 2 ), and a hydrogenic nodule from the Indian Ocean (D20-1B) (Ce­(IV)-sorbed MnO 2 ). The Ce L α1 (3d 5/2 → 2p 3/2 ) fluorescence line was selected using the 331 reflection of five Ge crystals of 100 mm diameter, spherically bent to a radius of 1.0 m. , The Bragg angle of the spectrometer was 84.7° in a vertical Rowland circle geometry.…”

“…Details on analytical precisions and determination of detection limits can be found in Batanova et al 42 HR-XANES. The Ce L3-edge HR-XANES spectra of single apatite grains and pressed pellets of the bulk sediments were measured at the French CRG FAME-UHD (BM16) beamline of the European Synchrotron Radiation Facility (ESRF) together with the following references: the Durango apatite from Gerin et al (2017) 38 (Ce(III)), Ce(NO3)3ꞏ6H2O (Ce(III)), cerianite (Ce(IV)O2), and an hydrogenic nodule from the Indian Ocean (D20-1B 43 ) (Ce(IV)-sorbed MnO2).…”

Density Functional Theory Modeling of the Oxidation Mechanism of Tl(I) by Birnessite

“…The oxidative uptake of thallium (Tl) on manganese dioxides (MnO 2 ) has received much attention over the last few years, − because of the high toxicity of this element − and its 10 7 geochemical partitioning between seawater and ferromanganese (FeMn) crust and nodule deposits from the global ocean . Thallium occurs in two oxidation states: monovalent (thallous cation; Tl­(I)) and trivalent (thallic cation; Tl­(III)).…”