Single-crystal Raman evidence for and x-ray analysis of the distorted square-pyramidal pentachlorothallate and pentachloroindate complexes in bis(tetraethylammonium) pentachlorothallate and bis(tetraethylammonium) pentachloroindate

A second polymorph of 1,1,4,4-tetramethylpiperazinium pentabromothallate(III)

“…In both cases, the Br ax ÐTlÐBr ax angles (ax is axial) were somewhat distorted from linearity and the TlÐBr ax bond distances were quite asymmetric, but signi®cantly longer than the TlÐBr eq distances (eq is equatorial). Thus, the anion in these two compounds was shown to have a similar structure to that found for [FeCl 5 ] 2À in its complex with a quaternized ammonium counter-cation (James et al, 1995), but is different from the distorted square-pyramidal [InCl 5 ] 2À anion found in its tetraethylammonium salt (Joy et al, 1975). During an evaluation of currently available commercial diffractometers having CCD detectors, data sets were collected from a series of crystals with known`dif®cult' structures (Linden, 1999).…”

Trimethylammonium hexachloroindate(III)

“…Crystallographic studies confirmed these conclusions for Et4N[InCl4], in which the anion is tetrahedral (Trotter, Einstein & Tuck, 1969) and (EhN)z [InC%], where the anion has C4v symmetry (Brown, Einstein & Tuck, 1969). Joy, Gaughan, Wharf, Shriver & Dougherty (1975) have proposed an alternative model of lower symmetry for InCl 2-, based on their isotropic refinement in space group P4, for which R is identical with that obtained in P4/n. The former requires almost twice as many variables as the latter, so that the X-ray data alone do not allow a decision as to the molecular symmetry.…”

The shapes and other properties of non-transition element complexes. 3. AB5

“…More serious exceptions to trigonal bipyramidal geometry arise with InCls2-and TICI52-. [18][19][20][21][22][23] In the crystal, isolated InCls2-ions occur with square pyramidal geometry (C4,,). The bond to the apical chlorine (A-Bap) is 2.415 Á and the somewhat longer basal chlorine bonds (A-Bba) are 2.456 A.…”