Crystal structures and crystal chemical relationships of kröhnkite- and collinsite-type compounds Na2Me²⁺(XO₄)₂ · 2 H₂O (X = S, Me = Mn, Cd; and X = Se, Me = Mn, Co, Ni, Zn, Cd) and K₂Co(SeO₄)₂ · 2 H₂O

Autor(en)

Manfred Wildner, Donka Stoilova

Abstrakt

The crystal structures of eight compounds with compositions A2Me2+(XO4)2 · 2H2O (A = Na, X = S, Me2+ = Mn, Cd; A = Na, X = Se, Me2+ = Mn, Co, Ni, Zn, Cd; and A = K, X = Se, Me2+ = Co) were investigated using single crystal X-ray CCD diffraction data. The Mn- and Cd-compounds crystallize in the monoclinic kröhnkite structure type [Na2Cu(SO4)2 · 2 H2O, space group P21/c], the Co-, Ni-, and Zn-selenates in the closely related triclinic structure type of collinsite [Ca2Mg(PO4)2 · 2 H2O, space group P1̅]. Both types are built up from infinite Me(XO4)2(H2O)2 chains, composed of MeO4(H2O)2 octahedra alternating with each two XO4 tetrahedra by sharing corners. A—O bonds and hydrogen bonds link the chains to layers and further on to the three-dimensional structures. The influence of the ionic radii of the various A, Me, and X cations on the distances between these structural units is discussed. Special attention is paid to polyhedral distortions as well as to individual peculiarities of the alkaline coordinations and the hydrogen bonding systems. Thus, the crystal chemical relationships between the two structure types as well as to isotypic copper compounds, which are characterized by the strong octahedral Jahn-Teller distortions, are elucidated.

Organisation(en)

Institut für Mineralogie und Kristallographie

Externe Organisation(en)

Bulgarian Academy of Sciences (BAS)

Journal

Zeitschrift für Kristallographie : international journal for structural, physical, and chemical aspects of crystalline materials

Band

218

Seiten

201-209

Anzahl der Seiten

9

ISSN

0044-2968

DOI

https://doi.org/10.1524/zkri.218.3.201.20751

Publikationsdatum

2003

Peer-reviewed

Ja

ÖFOS 2012

1051 Geologie, Mineralogie

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/bb0ae771-91ae-487c-964c-2b23c081af1c