Research output: Contribution to journal › Article
In situ ambient and higherature Raman spectroscopic studies of nyerereite (Na,K)2Ca(CO3)2: Can hexagonal zemkorite be stable at earth-surface conditions? / Golovin, A.V.; Korsakov, A.V.; Zaitsev, A.N.
In: Journal of Raman Spectroscopy, No. 10, 2015, p. 904-912.Research output: Contribution to journal › Article
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TY - JOUR
T1 - In situ ambient and higherature Raman spectroscopic studies of nyerereite (Na,K)2Ca(CO3)2: Can hexagonal zemkorite be stable at earth-surface conditions?
AU - Golovin, A.V.
AU - Korsakov, A.V.
AU - Zaitsev, A.N.
PY - 2015
Y1 - 2015
N2 - Copyright © 2015 John Wiley & Sons, Ltd.In this study we present Raman spectroscopy data obtained from a naturally occurring orthorhombic nyerereite (Na,K)2Ca(CO3)2from the Oldoinyo Lengai volcano (Tanzania) at ambient and high temperature. Nyerereite was heated up to 300C, 400C and 500C, and is believed to have been transformed at high temperatures to hexagonal β- and γ-phases similar to zemkorite, (Na,K)2Ca(CO3)2. There are no major differences in the chemical composition of natural nyerereite and zemkorite. However, Raman spectra reveal significant differences between the nyerereite at ambient temperature and the phases obtained in the course of all our higherature experiments. In situ measurements show that none of the higherature hexagonal phases are quenchable, even at very high cooling rates (up to 50-80C/min), and they transform to nyerereite at ambient temperature. Contrary to previous studies even the presence of high K2O (up to 7.5wt.%) did not stabilize the hexagonal structure during cooling. The
AB - Copyright © 2015 John Wiley & Sons, Ltd.In this study we present Raman spectroscopy data obtained from a naturally occurring orthorhombic nyerereite (Na,K)2Ca(CO3)2from the Oldoinyo Lengai volcano (Tanzania) at ambient and high temperature. Nyerereite was heated up to 300C, 400C and 500C, and is believed to have been transformed at high temperatures to hexagonal β- and γ-phases similar to zemkorite, (Na,K)2Ca(CO3)2. There are no major differences in the chemical composition of natural nyerereite and zemkorite. However, Raman spectra reveal significant differences between the nyerereite at ambient temperature and the phases obtained in the course of all our higherature experiments. In situ measurements show that none of the higherature hexagonal phases are quenchable, even at very high cooling rates (up to 50-80C/min), and they transform to nyerereite at ambient temperature. Contrary to previous studies even the presence of high K2O (up to 7.5wt.%) did not stabilize the hexagonal structure during cooling. The
U2 - 10.1002/jrs.4756
DO - 10.1002/jrs.4756
M3 - Article
SP - 904
EP - 912
JO - Journal of Raman Spectroscopy
JF - Journal of Raman Spectroscopy
SN - 0377-0486
IS - 10
ER -
ID: 4003569