No abstract

N.q.r. frequencies of 14 salts of SnCls2-, TeC162-, and PbC162-have been recorded in a n effort to observe possible differences in anion distortion which could result from the ' inert ' pair electrons of TeIV. There is no evidence of stereochemical activity of the TeIV ' inert ' pair as might be indicated by an increase in the number of chlorine resonance frequencies and/or anomalous changes in bond ionicity in any of the compounds studied. PbCIG2appears to be more sensitive to the cation than SnCls2-but the TeCIe2-ion is less sensitive. It is concluded that anion sensitivity to the cation is not readily predictable on the basis of the size alone.

No abstract

The title compound has been examined by single-crystal X-ray crystallography and crystallizes in the space-group P2,lc with Z = 2 in a unit cell of dimensions a = 8.555, b = 16.962, c = 7.1 22 a and p = 11 3-1 5". The structure was solved by conventional Fourier techniques and was refined anisotropically by full-matrix least-squares methods to R 0-039 using 1600 independent reflections measured by counter methods. The cation is regular and normal.The SnCla2-ion is tetragonally distorted with three crystallographically inequivalent Sn-CI bonds [2.414(4), 2.419(2), and 2.463(3) 81. the source of the distortion being CI . * . H-N hydrogen bonding between the long Sn-CI bonds of SnCIG2-and the cation. These results account very well for the marked splittings in the 35CI n.q.r. signals observed for this anion.RECENT n.q.r. measurements on SnClG2-, PbC1,2-, and Tech2-salts indicate that when the 4-chloropyridinium ion (4-ClpyH) is the counter cation, very large splittings in the chlorine resonance frequencies of the anion appear. N.q.r. spectroscopy can be used to detect chemical and crystallographic inequivalencies of nuclei having quadrupole moments. Crystallographic inequivalence generally leads to small splittings which are rarely >5% of the overall effect. However in [4-ClpyH]2SnC&, for example, resonance multiplets appear that are split by >15% of the overall effect. It is of importance to n.q.r. spectroscopy to know what sorts of interactions can generate such marked splittings in an I'vIC~,~-salt. To the general chemistry of tin it is important to know whether this cation has distorted the SnCh2-ion enough to produce a different anionic arrangement, such as a SnC1,-, C1ion pair. Finally, in the only crystallographic data available on the SnClG2the Sn-Cl bond lengths are either not known or determined approximately to be 2.41 & 0 . 0 5 4 . 1 0 h;.We therefore undertook a crystal structure determination of 4-chloropyridinium hexachlorostannate(Iv) . EXPERIMENTAL u = 8.555(9), b = 16*962(5), c = 7.122(7) A, p = 113.15" Cyystal Data

Es werden die NQR‐Frequenzen von 14 Salzen von SnClä ′, TeClä ′ und PbClä gemessen, um Unterschiede in der Anionenverschiebung zu beobachten, die vo dem "inerten" Elektronenpaar von TeIV herrühren kann.