Εξειδίκευση τύπου :	Άρθρο σε επιστημονικό περιοδικό
Τίτλος:	The nature of laponite: Pure hectorite or a mixture of different trioctahedral phases?
Δημιουργός/Συγγραφέας:	Christidis G.E. Aldana C. [EL] Χρυσικός, Γεώργιος Δ.[EN] Chryssikos, Georgios D. [EL] Γκιώνης, Βασίλης[EN] Gionis, Vassilis Kalo H. Stöter M. Breu J. Robert J.-L.
Εκδότης:	MDPI AG
Ημερομηνία:	2018
Γλώσσα:	Αγγλικά
ISSN:	2075-163X
DOI:	10.3390/min8080314
Περίληψη:	A series of laponites and synthetic OH-and fluorinated hectorites prepared from hydrothermal and melting experiments at both industrial and laboratory scale were examined with XRD and FTIR (MIR and NIR) to determine their mineralogical composition and possible compositional heterogeneity. The end materials contained both Li-and Na-bearing phases. The industrial hydrothermal OH-smectites prepared at low temperatures consist of random mixed layer hectorite-stevensite-kerolite with about 40–50% hectorite layers, the remaining being stevensite and kerolite at roughly equal proportions. The FTIR spectra of these smectites contain, besides the main Mg3 OH stretching/overtone bands at 3695–3690 and 7225–7214 cm−1, respectively, additional OH overtone bands at ~3716 and 7265 cm−1 (hydrated state). These bands might be linked to Mg2 LiOH stretching modes. The melt-derived smectites are kerolite-free but still contain stevensite layers, although the preparation methods involved heating in the excess of 1000◦ C. In these smectites Li might be partitioned to both octahedral and interlayer sites. Subsequent annealing of the melt-derived Mg-Li smectites caused migration of the exchangeable Li to the vacant octahedral due to the Hofmann-Klemen effect and thus decrease of the layer charge, as was indicated by the νO-D method. Hydrothermal synthesis of Mg-Li smectites at high temperature (400◦ C) and pressure (1 kbar), yielded pure hectorite without stevensite or kerolite domains.
Τίτλος πηγής δημοσίευσης:	Minerals
Τόμος/Κεφάλαιο:	8
Τεύχος:	8
Θεματική Κατηγορία:	[EL] Φυσική και θεωρητική χημεία[EN] Physical and theoretical chemistry
Λέξεις-Κλειδιά:	Hectorite Kerolite Laponite Smectite nanoparticles Stevensite Synthesis
Αξιολόγηση από ομότιμους (peer reviewed):	Ναι
Κάτοχος πνευματικών δικαιωμάτων:	© 2018 by the authors. Licensee MDPI, Basel, Switzerland.
Όροι και προϋποθέσεις δικαιωμάτων:	All Open Access, Gold, Green
Σημειώσεις:	Εθνικό 'Ίδρυμα Ερευνών, EIE; European Commission, EC; Deutsche Forschungsgemeinschaft, DFG: SFB 840 Funding: Research was funded from EU via the IMACS Erasmus Mundus project (TUC), the Deutsche Forschungsgemeinschaft (SFB 840) (Lehrstul für Anorganische Chemie, Universität Bayreuth) and internal funding (NHRF).
Εμφανίζεται στις συλλογές:	Ινστιτούτο Θεωρητικής και Φυσικής Χημείας (ΙΘΦΧ) - Επιστημονικό έργο