(CH3)3CCOOSbCl4: Structure Determination by Zeeman Perturbed NQR
A single crystal of tetrachloro(0,0-pivaloylato)antimony(V) has been studied at 77 K, byZeeman perturbed 35Cl NQR, using a FT-NQR pulsed spectrometer. The four lines at zero-field, ν1 = 27.6468, ν2= 27.3070, ν3= 25.7341 and ν4= 25.3438 MHz yield eight EFG tensors in themagnetic field, related by a twofold symmetry element in the crystal. The correspondingasymmetry parameters are η1, = 0.134, η2 = 0.13, η3= 0.07, and η4 = 0.09. The molecular structurededuced from the relative orientations of the principal Z-axes of the EFG tensors confirms that thehigher quadrupole coupling constants are associated with the chlorine atoms in equatorial positions,relative to the plane of the organic ligand, as predicted from NQR powder studies. It is concludedthat the crystal structure is monoclinic with two (class m or 2) or four (class 2/m) moleculesper unit cell. The molecular packing is such that the planes formed by equatorial or axial chlorineatoms are approximately at right angles to their symmetry related images.