Über die topochemische einphasige Reduktion von γ‐MnO₂

Abstract

BRENET und Mitarbeiterl) haben wohl als erste darauf hingewiesen, dass bei der Entladung von LECLANCHk-Zelkn y-MnO, seine Struktur zunachst nicht andert und dass im ersten Stadium der elektrolytischen Reduktion nur eine Gitterdehnung eintritt ,).Wir haben festgestellt, dass auch bei der chemischen Reduktion von y-MnO,, z. B. mit Hydrazin, zunachst nur eine Dehnung des Gitters stattfindet. Bis jetzt haben wir nur die stark fehlgeordnete Varietat von y-MnO, untersucht, wie sie bei elektrolytischer3) Herstellung und nach der Vorschrift von GLEMSER 4, aus Mangansulfat, Salpetersaure und Ammoniumpersulfat entsteht.Diese Varietat von y-MnO, gibt ein RONTGEN-Diagramm mit nur 5 Reflexen, sehr ahnlich dem Diagramm von 6-FeOOH5). Zwischen dieser stark fehlgeordneten Varietat von y-MnO, und Ramsdell it, einem seltenen MnO,-Mineral, scheint eine

Transformations of Synthetic Birnessite as Affected by pH and Manganese Concentration

“…The incorporation of Mn 2+ into the structure would change the Mn-O bond length of birnessite and cause a charge imbalance. Feitknecht et aL (1960) suggested that the structure becomes unstable and rearranges to that of a new phase if a sufficient amount of Mn was incorporated into the structure. Therefore, it is most likely that incorporation of Mn 2 § into the structure of birnessite subsequently induced spontaneous solid state rearrangement and reorientation of atoms in the birnessite crystal structure, leading to the transformation ofbirnessite into a series of new Mn minerals.…”

Effect of Manganese on the Transformation of Ferrihydrite into Goethite and Jacobsite in Alkaline Media

“…The distortion caused by the presence of Mn(III) in this type of structure can be expressed as the ratio of the undistorted to the distorted edges of the octahedron i.e., a"/a' (Feitknecht et al, 1960;Giovanoli and Stiihli, 1970). Here, a' is the length of the octahedron along the c axis, whereas a", the distorted edge, has a length a" = l/2k/b2/4 + c ~.…”

The Structure of Fully H-Inserted γ-Manganese Dioxide Compounds

“…In particular, peaks (221)/(240) and (061)/(002) coalesce into broad combined peaks as the microtwinning percentage approaches 100% (19). 3 This work for the first time investi- in a nonaqueous environment. The techniques were chosen known to have closely resembling X-ray diffraction patterns to those produced using the methods described to minimize unwanted subsidiary chemical reactions in an attempt to produce as far as possible materials reflecting above (22).…”

“…2 It is now well established that such materials act as defect has been given the name de Wolff disorder (2). host structures for H insertion (3)(4)(5)(6)(7). Although a new in-…”