caa a22 4500 378857592 CHVBK 20180305123338.0 cr unu---uuuuu 161128e20030301xx s 000 0 eng 10.1524/zkri.218.3.201.20751 doi (NATIONALLICENCE)gruyter-10.1524/zkri.218.3.201.20751 Crystal structures and crystal chemical relationships of kröhnkite- and collinsite-type compounds Na2Me2+(XO4)2 · 2 H2O (X [Elektronische Daten] S, Me = Mn, Cd; and X = Se, Me = Mn, Co, Ni, Zn, Cd) and K2Co(SeO4)2 · 2 H2O [M. Wildner, D. Stoilova] 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. © 2003 Oldenbourg Wissenschaftsverlag GmbH Crystallography nationallicence Inorganic chemistry nationallicence Organic chemistry nationallicence Wildner M. aut Stoilova D. aut Zeitschrift für Kristallographie - Crystalline Materials De Gruyter Oldenbourg 218/3(2003-03-01), 201-209 2194-4946 218:3<201 2003 218 zkri https://doi.org/10.1524/zkri.218.3.201.20751 text/html Onlinezugriff via DOI 1 research article jats NATIONALLICENCE 856 40 https://doi.org/10.1524/zkri.218.3.201.20751 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Wildner M. aut NATIONALLICENCE 700 1- Stoilova D. aut NATIONALLICENCE 773 0- Zeitschrift für Kristallographie - Crystalline Materials De Gruyter Oldenbourg 218/3(2003-03-01), 201-209 2194-4946 218:3<201 2003 218 zkri CC0 http://creativecommons.org/publicdomain/zero/1.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-gruyter