Stereochemical role of lone pairs in main-group elements. Part 4. The crystal structure at 120 K of bis(1,4,7,10,13-pentaoxacyclopentadecane)tin(II) bis[trichlorostannate(II)], confirming the sterically inactive tin lone pair

Abstract

The crystal structure of [SnL₂^]2+[SnCl₃^–]₂, (L = 1,4,7,10,13-pentaoxacyclopentadecane) has been determined from X-ray diffractometer data by Patterson and Fourier methods. Crystals are monoclinic, space group P2₁/a, with z= 2 in a unit cell of dimensions a= 8.879(1), b= 19.921(4), c= 10.202(3)Å, and β= 111.46(2)°. The structure was refined to R= 0.052 for 3 859 observed reflections. There are two tin(II) sites (ratio 1 : 2); one is sandwiched between two crown molecules in a complex cation in which the tin lone pair is not stereochemically active; the other site is occupied by trichlorostannate(II) anions. The Mössbauer spectroscopic parameters of the complex cation are discussed in the light of the structure and are interpreted within a framework in which covalency is not considered insignificant.