Articles | Volume 32, issue 4
Eur. J. Mineral., 32, 427–441, 2020
https://doi.org/10.5194/ejm-32-427-2020
Eur. J. Mineral., 32, 427–441, 2020
https://doi.org/10.5194/ejm-32-427-2020

Research article 30 Jul 2020

Research article | 30 Jul 2020

Na-feldspar: temperature, pressure and the state of order

Herbert Kroll et al.

Related authors

Comment on “Water decreases displacive phase transition temperature in alkali feldspar” by Liu et al. (2018)
Herbert Kroll and Peter Schmid-Beurmann
Eur. J. Mineral., 32, 167–170, https://doi.org/10.5194/ejm-32-167-2020,https://doi.org/10.5194/ejm-32-167-2020, 2020
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Cited articles

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Angel, R. J., Carpenter, M. A., and Finger, L. W.: Structural variation associated with compositional variation and order-disorder behavior in anorthite-rich feldspars, Am. Mineral., 75, 150–162, 1990. 
Armbruster, Th., Bürgi, H. B., Kunz, M., Gnos, E., Brönnimann, St., and Lieneret, Ch.: Variation of displacement parameters in structure refinements of low albite, Am. Mineral., 95, 135–140, 1990. 
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Bambauer, H. U., Bernotat, W., Breit, U., and Kroll, H.: Perthitic alkali feldspar as indicator mineral in the Central Swiss Alps. Dip and extension of the surface of the microcline/sanidine transition isograd, Eur. J. Mineral., 17, 69–80, 2005. 
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Short summary
Feldspars constitute about 60 % of the earth's crust. Na-feldspar, Na[AlSi3O8], is central to this mineral group. Its structural response to changing conditions of temperature and pressure is complicated. In particular, this applies to the distribution of Al and Si on the atomic sites of its crystal structure. We clarify how this distribution varies in thermodynamic equilibrium with external conditions and provide procedures that allow easy determination of the atomic distribution.