An electron microscopy study of the crystal growth of schwertmannite needles through oriented aggregation of goethite nanocrystals

Autor:	Franca Jones, William R. Richmond, Mitch Loan, James G. Hockridge
Rok vydání:	2009
Předmět:	Goethite Schwertmannite Iron oxide Crystal growth Condensed Matter Physics Inorganic Chemistry Crystallography chemistry.chemical_compound Ferrihydrite chemistry Transmission electron microscopy Phase (matter) visual_art Materials Chemistry visual_art.visual_art_medium Crystallite
Zdroj:	Journal of Crystal Growth. 311:3876-3882
ISSN:	0022-0248
DOI:	10.1016/j.jcrysgro.2009.06.023
Popis:	The formation of the iron oxyhydroxide schwertmannite has been monitored by time-resolved transmission electron microscopy (TEM) studies. Schwertmannite aggregates are found to form initially as spherical agglomerates of ferrihydrite crystallites, which then begin to grow characteristic needles on their surfaces. High-resolution images of the needles show that they are initially comprised of aligned goethite nanocrystals, which subsequently coarsen to form crystallographically coherent needles of goethite. Thus, needle formation on schwertmannite aggregates can be considered as the first stage in the phase transformation from schwertmannite to goethite. The results of this study suggest that schwertmannite is not a distinct mineral phase, but may be a mixture of ferrihydrite and poorly crystalline goethite with a distinctive morphology directed by the presence of surface-adsorbed sulfate anions.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::24b4c5d8260537194a2f32c7bc161820 https://doi.org/10.1016/j.jcrysgro.2009.06.023 Zobrazit plný text záznamu Full Text from ScienceDirect