Manganese oxide minerals: Crystal structures and economic and environmental significance
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TLDR
The crystal structures for todorokite and birnessite, two of the more common Mn oxide minerals in terrestrial deposits and ocean nodules, were determined by using powder x-ray diffraction data and the Rietveld refinement method.Abstract:
Manganese oxide minerals have been used for thousands of years—by the ancients for pigments and to clarify glass, and today as ores of Mn metal, catalysts, and battery material. More than 30 Mn oxide minerals occur in a wide variety of geological settings. They are major components of Mn nodules that pave huge areas of the ocean floor and bottoms of many fresh-water lakes. Mn oxide minerals are ubiquitous in soils and sediments and participate in a variety of chemical reactions that affect groundwater and bulk soil composition. Their typical occurrence as fine-grained mixtures makes it difficult to study their atomic structures and crystal chemistries. In recent years, however, investigations using transmission electron microscopy and powder x-ray and neutron diffraction methods have provided important new insights into the structures and properties of these materials. The crystal structures for todorokite and birnessite, two of the more common Mn oxide minerals in terrestrial deposits and ocean nodules, were determined by using powder x-ray diffraction data and the Rietveld refinement method. Because of the large tunnels in todorokite and related structures there is considerable interest in the use of these materials and synthetic analogues as catalysts and cation exchange agents. Birnessite-group minerals have layer structures and readily undergo oxidation reduction and cation-exchange reactions and play a major role in controlling groundwater chemistry.read more
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Karl K. Turekian,K. H. Wedepohl +1 more
TL;DR: A table of abundances of the elements in the various major units of the Earth's lithic crust with a documentation of the sources and a discussion of the choice of units and data is presented in this article.
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Immobilisation of high level nuclear reactor wastes in SYNROC
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Manganese Oxide Octahedral Molecular Sieves: Preparation, Characterization, and Applications
Yan-Fei Shen,Richard P. Zerger,Roberto N. DeGuzman,Steven L. Suib,L. Mccurdy,Donald I. Potter,C. L. O'Young +6 more
TL;DR: A thermally stable 3 x 3 octahedral molecular sieve corresponding to natural todorokite (OMS-1) has been synthesized by autoclaving layer-structure manganese oxides, which are prepared by reactions of MnO4- and Mn2+ under markedly alkaline conditions.
Journal ArticleDOI
The interaction of metal ions at the hydrous manganese dioxide-solution interface
TL;DR: In this article, the adsorption of metal ions was measured and alkalimetric titrations were performed on a synthetic sample of hydrous manganese dioxide, and the affinity of the metals for the surface followed the order: Mg.
Journal Article
Crystal structure determinations of synthetic sodium, magnesium, and potassium birnessite using TEM and the Rietveld method
Jeffrey E. Post,David R. Veblen +1 more
TL;DR: In this article, a determination of the structure cristalline des sous-mailles des phases synthetiques analogues a la birnessite is made in Na, Mg and K.