Crystal chemistry of the M₁^1+,2+-M₂^2+,3+-(H)-arsenites

Author(s)

Tamara Đorđević

Abstract

The crystal structures among M1-M2-(H)-arsenites (M1 = Li+, Na+, K+, Rb+, Cs+, Ca2+, Sr2+, Ba2+, Cd2+, Pb2+; M2 = Mg2+, Mn2+,3+, Fe2+,3+, Co2+, Ni2+, Cu2+, Zn2+) are less investigated. Up to now, only the structure of Pb3Mn(AsO3)2(AsO2OH) was described. The crystal structure of hydrothermally synthesized Na4Cd7(AsO3)6 was solved from the single-crystal X-ray diffraction data. Its trigonal crystal structure [space group Requation image, a = 9.5229(13), c = 19.258(4) Å, ? = 120°, V = 1512.5(5) Å3, Z = 3] represents a new structure type. The As atoms are arranged in monomeric (AsO3)3- units. The surroundings of the two crystallographically unique sodium atoms show trigonal antiprismatic coordination, and two mixed Cd/Na sites are remarkably unequal showing tetrahedral and octahedral coordinations. Despite the 3D connection of the AsO3 pyramids, (Cd,Na)Ox polyhedra and NaO6 antiprisms, a layer-like arrangement of the Na atoms positioned in the hexagonal channels formed by CdO4 deformed tetrahedra and AsO3 pyramids in z = 0, 1/3, 2/3 is to be mentioned. These pseudo layers are interconnected to the 3D network by (Cd,Na)O6 octahedra. Raman spectra confirmed the presence of isolated AsO3 pyramids.

Organisation(s)

Department of Mineralogy and Crystallography

Journal

Zeitschrift für Anorganische und Allgemeine Chemie

Volume

641

Pages

1863-1868

No. of pages

6

ISSN

0044-2313

DOI

https://doi.org/10.1002/zaac.201500252

Publication date

07-2015

Peer reviewed

Yes

Austrian Fields of Science 2012

104011 Materials chemistry, 105113 Crystallography, 104024 X-ray structural analysis

Keywords

ASJC Scopus subject areas

Inorganic Chemistry

Portal url

https://ucrisportal.univie.ac.at/en/publications/crystal-chemistry-of-the-m112m223harsenites(e983ebeb-6ab8-4390-9c4a-07e656d64330).html