CH3Br







 









Deuterium and Bromine


Nuclear Quadrupole Coupling Constants


in Methyl Bromide


 








 
 
  





 








Deuterium nqcc's in fully deuterated methyl bromide were determined by Kukolich and Cogley [1].  The bromine nqcc in the normal species was measured by Carocci et al. [2],  Osipov and Grabois [3],  Arimondo et al. [4], Ramos and Drouin [5], Demaison et al. [6], and Thomas et al. [7].  Graner [8] determined an equilibrium structure.

 








Calculation of the deuterium and bromine nqcc's was made here on the equilibrium structure.  These nqcc's are compared with the experimental values in Tables 1 and 2.  Structure parameters and atomic coordinates respectively are given in Tables 3 and 4.

 








In Table 1, the subscripts u,v,w refer to the coordinate axes defined in Table 4.  The u-axis is along the threefold symmetry axis.  The nqcc's given with these subscripts are those for the H atom in the uv-plane.

 








   






Table 1. Deuterium nqcc's in CD3Br (kHz).

   








Calc.
Expt. [1]
   






2H Xuu
- 65.1 -
 64.5(3)


Xvv
164.6



  Xww
- 99.5




Xuv
- 80.9



 







Xxx
- 90.7




Xyy
- 99.5




Xzz
190.3




ETA
0.046




Øz,u
72.42




Øu,CD
72.27




Øz,CD
  0.15



 







 








 








   






Table 2. Bromine nqcc's in CH3Br (MHz).
   









Calc.
Expt.
   






79Br Xzz
573.99
577.1088(57) [2]






577.1300(18) [3]






577.143(8) [4]






577.1343(31) [5]






577.06(20) [6]






577.3 [7]

 






81Br Xzz
479.55
482.1030(57) [2]






482.1308(17) [3]






482.130(18) [4]






482.1354(31) [5]






482.141(8) [9]






482.05(20) [6]






482.4 [7]

 







 








The difference between calculated and experimental [2] 79Br nqcc's is 3.12 MHz (0.54 %).  For 81Br, the difference is 2.55 MHz (0.53 %).
   








 


Table 3. CH3Br Structure parameters, re [8] (Å and degrees).






CBr 1.9340


CH 1.0823


HCH 111.157


 
















Table 4. Atomic coordinates, re
(More figures are shown than are significant.)
 









  u (Å)
  v (Å)
  w (Å)
 







H - 1.883148
1.030906
0.0

H - 1.883148 - 0.515453 ± 0.892791

C - 1.553593
0.0
0.0

Br
0.380407
0.0
0.0


 








 








[1] S.G.Kukolich and C.D.Cogley, J.Chem. Phys. 76,1685(1982).

[2] S.Carocci, P.Minguzzi, M.Tonelli, and A.DiLieto, J.Mol.Spectrosc. 160,359(1993).

[3] B.D.Osipov and M.N.Grabois, Opt. Spectrosc.(USSR) 58,702(1985).

[4] E.Arimondo, J.G.Baker, P.Glorieux, T.Oka, and J.Sakai, J.Mol.Spectrosc. 82,54(1980).

[5] M.Ramos and B.J.Drouin, J.Mol.Spectrosc. 269,187(2011).

[6] J.Demaison, D.Boucher, J.Burie, and A.Dubrulle, J.Mol.Spectrosc. 61,141(1976).

[7] W.J.O.Thomas, J.T.Cox, and W.Gordy, J.Chem.Phys. 22,1718(1954).

[8] G.Graner, J.Mol.Spectrosc. 90,394(1981).

[9] K.-F.Dossel and D.H.Sutter, Z.Naturforsch. 34a,469(1979).

 








J.L.Duncan, J.Mol.Struct. 6,447(1970): re structure, CBr = 1.933(2) Å,  CH = 1.086(3) Å, and HCH = 111o10'(25').  On this structure, calculated Xzz = 573.89 and 479.46 MHz respectively for 79Br and 81Br. 

J.R.Williams and S.G.Kukolich, J.Mol.Spectrosc. 74,242(1979):  In CH3Br, eqQ(79Br) = -577.08(15) and eqQ(81Br) = -482.18(15) MHz.  In CD3Br, eqQ(79Br) = -575.66(15) and eqQ(81Br) = -480.89(15) MHz.

 








 








CH2Br2 SiH3Br SiF3Br GeH3Br

CD3F CD3Cl CF3Br CF3Cl

HCC-CH3







 








 








Table of Contents




Molecules/Deuterium




Molecules/Bromine




Summary/Methyls  Deuterium nqcc's in substituted methanes.

 








 













CH3Br.html






Last Modified 23 July 2011