ISSN print edition: 0366-6352
ISSN electronic edition: 1336-9075
Registr. No.: MK SR 9/7

Published monthly
 

The crystal chemistry of complex fluorides of the general formula A2MF6 The refinement of the structure (NH4)2SiF6

F. Hanic

Slovak Academy of Sciences, Bratislava 9

 

Abstract: The crystal chemistry of hexafluorocomplexes of the general formula A2MF6, where A is NH4, K, Rb, Cs, and Tl and M is Si, Ti, V, Cr, Mn, Co, Ni, Ge, Zr, Rh, Pd, Sn, Hf, Os, Ir, Pt, Pb, and the exactness of the structure of (NH4)2SiF6 are described. A2MF6 crystallizes in 3 forms: the cubic (C) of the structural type K2PtCl6, the hexagonal (H) of the structural type K2MnF6, and the trigonal form (T) of the structural type K2GeF6. All 3 forms are closely related with a tight arrangement of A+ and F- ions contg. isolated groups of MF62- with an octahedral arrangement. The basic structural units of all 3 forms are parallel layer-triplets of A-MF6-A compn. A close-packed assembly of atoms of the particular form can be achieved by a parallel translation of the layer-triplets in such a way that every 2nd T or 3rd H or 4th C layer-triplet is identical with the 1st one. The sequence of the layer-triplets is aaa... in the T form, ababab... in the H form, and abcabc... in the C form. Cubic crystals of (NH4)2SiF6 are isostructural with (NH4)2PtCl6. The structure of (NH4)2SiF6 was more exactly defined from the least sqs. of the 3-dimensional x-ray data. The interat. distance Si-F in the octahedron SiF6 was detd. to be 1.676 A. All NH4+ groups are coordinated by 12F- at 3.00 A.

Full paper in Portable Document Format: 2010a738.pdf (in Slovak)

 

Chemical Papers 20 (10) 738–751 (1966)

Wednesday, December 07, 2022

IMPACT FACTOR 2021
2.146
SCImago Journal Rank 2021
0.365
SEARCH
Advanced
VOLUMES
European Symposium on Analytical Spectrometry ESAS 2022
© 2022 Chemical Papers