A single-crystal X-ray and Raman spectroscopic study of hydrothermally synthesized arsenates and vanadates with the descloizite and adelite structure types

Author(s)
Tamara Đorđević, Uwe Kolitsch, Lutz Nasdala
Abstract

Studying the reason for the formation of two structural sub-types, seven arsenate and vanadate compounds of descloizite and adelite groups [specifically (1) CdCo(OH)(AsO

4), (2) CdCu(OH) (AsO

4), (3) SrCo(OH)(AsO

4), (4) SrZn(OH)(AsO

4), (5) SrCu(OH)(VO

4), (6) CdCo(OH)(VO

4), and (7) CdCu(OH)(VO

4) (bold numbers throughout paper refer to these compounds)] were synthesized under low-temperature hydrothermal conditions. 1-2 and 6-7 are isostructural with descloizite, and 3-5 are with adelite-group minerals and several synthetic compounds. Together with a sample of conichalcite, (8) CaCu(OH)(AsO

4), they were investigated using single-crystal X-ray diffraction [R(F) = 0.0153-0.0283 for 1-5 and 8; for 6 and 7, R(F) = 0.0603 and 0.0444, respectively] and Raman spectroscopy. Although crystallizing in different orthorhombic space groups, the atomic arrangements of descloizite-(Pnam) and adelite-(P2

12

12

1) type compounds adopt the same topology: the atomic arrangement is characterized by M2O

6 octahedrons (M2 = Mg

2+, Al

3+, Mn

2+,3+, Fe

2+, Co

2+, Ni

2+, Cu

2+, Zn

2+) edge-linked into chains. These chains are interconnected by XO

4 tetrahedrons (X = Si

4+, P

5+, V

5+, As

5+, Mo

6+) into a three-dimensional framework. Cavities host M1 atoms (M1 = Na

+, Ca

2+, Cd

2+, Hg

2+, Pb

2+); their coordination varies from 7 for descloizite-type representatives to 8 for adelite-type structures. The OH stretching frequencies in the Raman spectra are in good agreement with the observed O-H...O donor-acceptor distances. A detailed discussion of the crystal chemistry of these compounds and their influence on the space-group symmetry indicate a distinct dependence of the structural changes on the average ionic radii (r

M1 + r

X)/2.

Organisation(s)
Department of Mineralogy and Crystallography
External organisation(s)
Naturhistorisches Museum Wien (NHM)
Journal
American Mineralogist: an international journal of earth and planetary materials
Volume
101
Pages
1135-1149
No. of pages
15
ISSN
0003-004X
DOI
https://doi.org/10.2138/am-2016-5422
Publication date
05-2016
Peer reviewed
Yes
Austrian Fields of Science 2012
104026 Spectroscopy, 105116 Mineralogy, 105113 Crystallography
Keywords
ASJC Scopus subject areas
Geochemistry and Petrology, Geophysics
Portal url
https://ucrisportal.univie.ac.at/en/publications/a-singlecrystal-xray-and-raman-spectroscopic-study-of-hydrothermally-synthesized-arsenates-and-vanadates-with-the-descloizite-and-adelite-structure-types(789fe90c-1b67-4160-885b-57b4e5ad29ec).html