SiH2Cl2
		Chlorine
	Nuclear Quadrupole Coupling Constants
		in Dichlorosilane
	The complete 35Cl nqcc tensor has been measured in dichlorosilane by Hensel et al. [1].  An earlier measurement of the diagonal components was made by Davis and Gerry [2].  Molecular structures - ground state effective, substitution, ground state average, and equilibrium - have been determined by Davis et al. [3].
	Chlorine nqcc's calculated on the equilibrium structure are compared with the experimental results of Henzel et al. in Table 1.  Equilibrium structure parameters are shown in Table 2.
	In Table 1, RMS is the root mean square difference between calculated and experimental diagonal nqcc's (percentage of the average of the magnitudes of the experimental nqcc's).  RSD is the calibration residual standard deviation for the B1LYP/TZV(3df,2p) model for calculation of the chlorine nqcc's.
	Subscripts a,b,c refer to the principal axes of the inertia tensor; x,y,z to the principal axes of the nqcc tensor.  The nqcc y-axis is chosen coincident with the inertia c-axis, these are perpendicular to the molecular plane.  Ø (degrees) is the angle between its subscripted parameters.  ETA = (Xxx - Xyy)/Xzz.
	Table 1. Chlorine nqcc's in CH2Cl2 (MHz).  Calculation was made on the equilibrium molecular structure of Davis et al. [3].     Calc. Expt. [1]     35Cl Xaa - 20.69 - 20.4150 Xbb - 0.26 - 0.3095(19) Xcc 20.95 20.7245(19) Xab ± 26.58 ± 26.099(74)   RMS 0.21 (1.5 %) RSD 0.49 (1.1 %)   Xxx 18.00 17.60(13) Xyy 20.95 20.7245(19) Xzz - 38.95 - 38.33(13) ETA 0.076 0.082(3) Øz,a 34.49 34.467(27) Øa,SiCl 35.16 Øz,SiCl   0.67     37Cl Xaa - 16.31 Xbb - 0.20 Xcc 16.51 Xab ± 20.95
	The angle between the two z-axes is 1.34o larger than the ClSiCl angle.  This is typical of  the XCl2 dichloride moiety.
	Table 2.  Molecular structure parameters re [3] (Å and degrees). SiCl 2.0316 SiH 1.4671 ClSiCl 109.67 HSiH 112.45
	[1] K.D.Henzel, W.Jäger, M.C.L.Gerry, and I.Merke, J.Mol. Spectrosc. 158,131(1993).
	[2] R.W.Davis and M.C.L.Gerry, J.Mol.Spectrosc. 60,117(1976).
	[3] R.W. Davis, A.G.Robiette, and M.C.L.Gerry, J.Mol.Spectrosc. 85,399(1981).
	Related ...
	"An ab initio Study of the Molecular Electric-field Gradients of the Chlorosilanes" H.U.Suter, D.M.Maric, and P.F.Meier, Z.Naturforsch. 51a,41(1996).
	SiH3Cl		SiHCl3		SiCl2		CH3SiCl2CH3
	GeH3Cl		SiCl		(CH3)3SiCl		OCl2
	CH3Cl		CH2Cl2		CHCl3		SCl2
	Table of Contents
	Molecules/Chlorine
						SiH2Cl2.html
						Last Modified 4 June 2003