CH2I2

























 









Iodine


Nuclear Quadrupole Coupling Constants


in Methylene Iodide


 








 








127I nqcc's in, and a heavy atom rz structure of methylene iodide were determined by Kisiel et al. [1].

 








127I nqcc's were calculated here on the rz structure.  These are compared with the experimental values in Table 1.  Molecular structure parameters are given 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/6-311G(df,p) model for calculation of the 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 ICI plane.  Ø (degrees) is the angle between its subscripted parameters.  ETA = (Xxx - Xyy)/Xzz.

 








 







 
   






Table 1.  Iodine nqcc's in CH2I2 (MHz).  Calc. = B1LYP/6-311G(df,p).  Calculation was made on the rz structure.
   









Calc.
Expt. [1]
   






127I Xaa - 1190.5 - 1180.90(13)


Xbb
  149.6
  144.238(70)


Xcc
1040.9
1036.662(70)


Xab ± 1372.6 ± 1358.85(54)

 







RMS
  6.8 (0.87 %)




RSD
15.2 (1.23 %)



 







Xxx
1007.0
  993.4(10)


Xyy
1040.9
1036.66(9)


Xzz - 2047.9 - 2030.1(5)


ETA
0.0166
0.0213


Øz,a
31.99
32.00(1)


Øa,CI
33.08
33.08 *


Øz,CI
  1.10
  1.08 *

 







 








* Calculated here, rz structure.





 













Table 2.  Methylene Iodide.  Molecular structure parameters, rz [2] (Å and degrees).  CH and HCH are assumed values.








CI 2.1364(6)



CH
 1.078(2)



ICI 113.83(5)



HCH 113.3(3)



 








 








[1] Z.Kisiel, L.Pszczólkowski, W.Caminati, and P.G.Favero, J.Chem.Phys. 105,1778(1996).

[2] Z.Kisiel, L.Pszczólkowski, W.Caminati, and P.G.Favero, J.Mol.Spectrosc. 189,283(1998).

 








 








CH3I CH3Br CH3Cl CH2ICl

CH3CH2I CH2Br2 CH2Cl2 CHFClI

 








 








Table of Contents




Molecules/Iodine




 








 













CH2I2.html






Last Modified 9 Dec 2008