CuSeO4 and Cu(SeO3OH)(2)6H(2)O, two novel copper-selenium(VI) oxysalts

Author(s)
Herta S. Effenberger, Gerald Giester, Manfred Wildner
Abstract

The two new copper(II) salts Cu(SeO

4) and Cu(SeO

3OH)

2·6H

2O were synthesized at low-temperature hydrothermal conditions (220 °C), and room temperature, respectively. Their atomic arrangements were studied based on single-crystal X-ray investigations [P2

1/n, a = 4.823(1), b = 8.957(2), c = 6.953(1) Å, β = 94.82(1)°, Z = 4; P1 ¯ , a = 6.133(1), b = 6.303(1), c = 8.648(2) Å, α = 70.45(1), β = 84.60(1), γ = 73.44(1)°, Z = 1]. Cu(SeO

4) adopts the MnAsO

4 structure type. It exhibits structural as well as topological relations with two formerly known isochemical compounds. They crystallize in the structure type ZnSO

4 (mineral name zincosite, Pnma) respectively NiSO

4 (Cmcm). The two minerals dravertite, CuMg(SO

4)

2, and hermannjahnite, CuZn(SO

4)

2, are isotypic with CuSeO

4-P2

1/n; interestingly, also α-NaCu(PO

4) belongs to this structure type: some rotation of the XO

4 group allows a supplementary position for the Na atom. — Cu(SeO

3OH)

2·6H

2O represents a new structure type. The protonated selenate group shows an extended Se—O

h bond distance (1.695 Å) as compared to the other Se—O bonds (1.614 to 1.626 Å). One OH dipole of the three independent H

2O molecules represents a rather free hydrogen bond. For the other H atoms, the O—H···O lengths vary from 2.585 to 2.799 Å. Interestingly, the distance O

w7···O

w7 of only 2.791 Å does not represent an edge in a coordination polyhedron and it is not preliminary involved in the hydrogen bond scheme. All Cu

2+ ions in the two title compounds are in a pronounced [4 + 2] coordination. The Cu

2+[4+2] atoms in Cu(SeO

4) are linked to chains along [100]; in Cu(SeO

3OH)

2·6H

2O they are not connected among each other.

Organisation(s)
Department of Mineralogy and Crystallography
Journal
Mineralogy and Petrology
Volume
117
Pages
307-315
No. of pages
9
ISSN
0930-0708
DOI
https://doi.org/10.1007/s00710-022-00809-8
Publication date
2023
Peer reviewed
Yes
Austrian Fields of Science 2012
105116 Mineralogy, 105105 Geochemistry
Keywords
ASJC Scopus subject areas
Geochemistry and Petrology, Geophysics
Portal url
https://ucrisportal.univie.ac.at/en/publications/8b165ebd-882f-4e8d-af48-13db586925d9