(y=3, 4 and 5), were investigated by means of the nuclear quadrupole resonance (NQR) due to 35Cl and the Mossbauer effect due to 119Sn . The NQR-frequencies were observed at the temperature of liquid nitrogen and room temperature; they were found to range from 17.656 to 21.439MHz. The Mossbauer effect was investigated only at the temperature of liquid nitrogen; it resulted in isomer shifts ranging from 0.275 to 0.350mm/sec.The NQR-frequency and the isomer shift decreased with an increase in the number of water molecules in the hydrates, and the relationship between the NQR-frequency and the isomer shift was nearly linear. This relation was interpreted in terms of the transfer of the s-electrons of the tin atom to the chlorine atoms. Furthermore, it was revealed that there was a significant difference between the Sn-Cl bond of the hydrates and that of ammonium chlorostannate.It is well-known that tin(IV) chloride forms various hydrates but their structures have not been determined by any means except the Raman spectra.1) Tin(IV) chloride and its hydrates are suitable for investigating the Sn-Cl bond, since the electronic structures of the tin and chlorine atoms can be investigated by means of the Mossbauer effect due to 119Sn and the nuclear quadrupole resonance due to 35Cl.The molecular complexes of tin(IV) chloride with organic or inorganic compounds containing oxygen or nitrogen atoms have thus far investigated by means of NQR2,3) and the Mossbauer effect. [4][5][6][7][8]

Molecular complexes of tin tetrachloride with some aliphatic compounds, such as alcohols and esters, were investigated by means of the Mössbauer effect due to 119Sn, irradiation being made by 23.8 keV γ-rays from the 119mSn in tin dioxide. Most of these complexes show quadru-pole splittings resulting from the addition of organic molecules to tin tetrachloride, although broad absorption curves are observed in some cases. The isomer shifts range from 0.30 to 0.45 mm/sec. They are much smaller than that of tin tetrachloride itself. The results are interpreted by taking account of the electronic structures of the complexes.

35Cl NQR spectra in SnCl4·2Me2O and SnCl4·2Et2O have been observed. Three crystal modifications of SnCl4·2Me2O have been found. A cis geometry is suggested for one of them, and a trans geometry for the remainder. A transformation between the cis and trans isomers in the solid state is indicated. The Zeeman effect on single crystals of cis-SnCl4·2Me2O and SnCl4·2Et2O has provided detailed information on bond angles and bond character. It is confirmed that the molecular geometry of cis-SnCl4·2Me2O belongs to the C2 group and that SnCl4·2Et2O has a trans geometry. The η values of the Cl atoms in cis-SnCl4·2Me2O are negligibly small and those of the Cl atoms in SnCl4·2Et2O are 0.11. The relatively small η values for the latter are ascribed to π bonding between the Sn and Cl atoms.

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