Nitrogen and Chlorine

Nuclear Quadrupole Coupling Constants

in Nitrogen Trichloride




Cazzoli, Favero, and Dal Borgo [1] determined for nitrogen trichloride a substitution molecular structure and, for chlorine, a bond axis quadrupole coupling constant.
Calculation was made here of the chlorine and nitrogen nqcc's on the substitution structure.  The results are given in Table 1.  Structure parameters and atomic coordinates are given in Tables 2 and 3.
Coordinate Systems
Xuu is the component of the nqcc tensor along the threefold symmetry axis.  Corresponding to the atomic coordinates given below in Table 3, Xvv and Xww are the components along the v- and w- axes for the Cl atom in the uv-plane.
The subscripts x,y,z refer to the principal axes of the nqcc tensor.  The nqcc y-axis is chosen coincident with the w-axis.  Ø (degrees) is the angle between its subscripted parameters.  ETA = (Xxx - Xyy)/Xzz.



Table 1.  Nitrogen and Chlorine nqcc's in NCl3 (MHz).

Expt. [1]


14N Xzz - 5.881
35Cl Xuu   36.75
Xvv - 88.61
  Xww   51.86
Xuv   48.10
Xxx   53.08
Xyy   51.86
Xzz - 104.94 - 108(3) *
ETA - 0.012
Øz,u   71.25
Øu,NCl   68.89
Øz,NCl     2.36
37Cl Xuu   28.96
Xvv - 69.84
Xww   40.87
Xuv   37.91


* Bond axis value.  ETA = 0 assumed.  Ref. [1].
The pyramid formed by the z-principal axes of the three Cl nqcc tensors is somewhat 'flatter' than the molecular pyramid.  This is typical of the pyramidal trichlorides.
Table 3. Molecular structure parameters, rs [1] (Å and degrees).
NCl 1.7535
ClNCl 107.78
Table 4. Atomic coordinates, rs
(More figures are shown than are significant.)
  u (Å)   v (Å)   w (Å)
Cl - 0.076222 1.635818 0.0
Cl - 0.076222 - 0.817909 ± 1.416660
N 0.555333 0.0 0.0

[1] G.Cazzoli, P.G.Favero, A.DalBorgo, J.Mol.Spectrosc. 50,82(1974).

NH3 NF3 (CH3)3N NFH2
AsCl3 SPCl3 CFCl3 CH3CCl3



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Last Modified 22 May 2003