ISSN:
0018-019X
Schlagwort(e):
Chemistry
;
Organic Chemistry
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Chemie und Pharmazie
Notizen:
The authors investigate the reaction products formed, when Fe(H2O)36+ is deprotonated in perchlorate solutions. When a small amount of base is added, metastable solutions containing the ions Fe(H2O)3+, Fe(H2O)5OH2+, Fe2(H2O)8(OH)4+ and Fe(H2O)4(OH)+ are formed, and α-FeOOH slowly crystallises out. In a narrow intermediate range immediately after adding the base, colloidal amorphous Fe(OH)3 and crystalline α-FeOOH are formed. If more base is added a dark brown solution of colloidal amorphous Fe(OH)3 results, in which the crystallisation of α-FeOOH, under certain conditions also of γ-FeOOH, begins after an induction period of several days. Only when a nearly equivalent amount of base is added, Fe(OH)3 is precipitated. On ageing, this changes partly into α-Fe2O3, partly into α-FeOOH, a rather large amount remaining amorphous. In all the systems, no stable state is reached at room temperature, even after years. If a small amount of Fe2+ ions is coprecipitated, a complete crystallisation of the amorphous hydroxide to α-FeOOH takes place. The mechanism of the formation of the crystalline phases is discussed.
Zusätzliches Material:
14 Ill.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1002/hlca.19620450127
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