CF2Cl2
		Chlorine
	Nuclear Quadrupole Coupling Constants
		in Dichlorodifluoromethane
	35Cl nqcc's in dichlorodifluorormethane have been determined by Baskakov, et al. [1], Takeo and Matsumura [2], and Su and Beeson [3].  Davis et al. [4] determined substitution, effective, and average structures.  Takeo and Matsumura [2] and Su and Beeson [3] also determined substitution structures.
	Chlorine nqcc's were calculated here on the substitution structure of Davis et al. and are compared with the experimental nqcc's [1] in Table 1.  Structure parameters are compared 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 CF2Cl2 (MHz).  Calculation was made on the substitution molecular structure of Davis et al. [4].     Calc. Expt. [1]     35Cl Xaa - 45.08 - 43.688(33) Xbb   6.11   4.6905 Xcc 38.98 38.9975 Xab ± 54.09 ± 52.7(46)   RMS 1.15 (3.9 %) RSD 0.49 (1.1 %)   Xxx 40.35 38.5 * Xyy 38.98 38.9975 Xzz - 79.32 - 77.5 ETA - 0.017 - 0.006 Øz,b 57.66 57.33 Øb,CCl 56.3 56.3 Øz,CCl   1.4   1.0     37Cl Xaa - 35.53 Xbb   4.81 Xcc 30.72 Xab ± 42.63
	* Calculated here from the experimental data.
	The angle between the two z-axes is 2.8o larger than the ClCCl angle.  This is typical of  the XCl2 dichloride moiety.
	Table 2.  Molecular structure parameters (Å and degrees). rs [4] ro [4] rz [4] rs [2] rs [3] CCl 1.744 1.742 1.745 1.744 1.738 CF 1.347 1.349 1.347 1.345 1.358 FCF 106.2 105.9 106.2 106.23 105.4 ClCCl 112.6 113.0 112.7 112.55 113.2
	[1] O.I.Baskakov, S.F.Dyubko, A.A.Katrich, V.V.Ilyushin, and E.A.Alekseev, J.Mol.Spectrosc. 199,26(2000).
	[2] H.Takeo and C.Matsumura, Bull.Chem.Soc.Jpn. 50,636(1977).
	[3] C.F.Su and E.L.Beeson Jr., J.Chem.Phys. 66,330(1977).
	[4] R.W. Davis, M.C.L.Gerry, and C.J.Marsden, J.Mol. Spectrosc. 101,167(1983).
	CF3Cl		CFCl3		CH2FCl		CHF2Cl
	CH3Cl		CH2Cl2		CHCl3
	Table of Contents
	Molecules/Chlorine
						CF2Cl2.html
						Last Modified 4 June 2003