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Über ein‐ und zweiphasige Reduktion von γ‐MnO 2 durch Zimtalkohol
Author(s) -
Giovanoli R.,
Bernhard K.,
Feitknecht W.
Publication year - 1968
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.19680510214
Subject(s) - chemistry , phase (matter) , discontinuity (linguistics) , matrix (chemical analysis) , manganite , reduction (mathematics) , crystallography , condensed matter physics , organic chemistry , geometry , physics , mathematical analysis , mathematics , chromatography , ferromagnetism
The reduction of γ‐MnO 2 with cinnamic alcohol in xylene at 90° leads (1) to γ‐MnOOH in a double phase reaction with germination if the α‐MnO 2 is extremely disperse, and (2) to α‐MnOOH in a strictly topotactical (single phase) reaction without germination if the γ‐MnO 2 is relatively well crystallised. The hexagonality of the densest packed oxygens is not a linear function of the reduction rate but shows a discontinuity when about half of the Mn 4+ are reduced, which is consistent with results of G ABANO . The αMnOOH obtained by this reaction shows still the selective and asymmetric X‐ ray and electron reflection broadening of the reactant. Hence, the authors consider the product to possess an intergrowth structure of a Groutite matrix with statistically and layerwise distributed Manganite microdomains, according to a model proposed by DE W OLFF for α‐MnO 2 . The domains are supposed to have the size of one cell only in the b direction, and of a few cells in the a direction, and to be present in relatively small concentration.