Hydrogen-bonding system in amarillite, NaFe(SO₄)₂(H₂O)₆

Author(s)

Zhuming Yang, Gerald Giester

Abstract

The crystal structure of amarillite, NaFe(SO4)2(H2O)6, was redetermined from a single crystal from Xitieshan, Qinghai Province, China. In complement to previous work, all non-H atoms were refined with anisotropic displacement parameters and H-atoms were located by difference Fourier methods and refined from X-ray diffraction data. The structure can be formally described by octahedral-tetrahedral "sheets" of corner-sharing [NaO4(H2O)2] octahedra and (SO4) tetrahedra, which constitute a structural sheet with composition [Na(SO4)2(H2O)2]3- extending parallel to (001). The resultant sheets are held together by interstitial Fe3+ cations and hydrogen bonds. The [NaO4(H2O)2] octahedra donate four hydrogen bonds to the oxygen atoms of neighboring (SO4) tetrahedra, thus strengthening connections in three dimensions. The interstitial [FeO2(H2O)4] octahedra are linked by eight hydrogen bonds to the vertices of the adjacent octahedral-tetrahedral sheets, further stabilizing the crystal structure of amarillite. The FTIR spectrum of amarillite shows a strong absorption between 3000 cm-1 and 3500 cm-1 with maxima at ∼3110cm-1 and ∼3442 cm-1, which is in accordance with the O-H···O distances derived from structure data.

Organisation(s)

Department of Mineralogy and Crystallography

External organisation(s)

Chinese Academy of Sciences (CAS)

Journal

European Journal of Mineralogy: an international journal of mineralogy, geochemistry and related sciences

Volume

28

Pages

953-958

No. of pages

6

ISSN

0935-1221

DOI

https://doi.org/10.1127/ejm/2016/0028-2567

Publication date

06-2016

Peer reviewed

Yes

Austrian Fields of Science 2012

105116 Mineralogy, 105113 Crystallography

Keywords

ASJC Scopus subject areas

Geochemistry and Petrology

Portal url

https://ucrisportal.univie.ac.at/en/publications/0c39b1ed-8e97-40d3-bbd6-970aa9378b18