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C2H2N2S
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Nitrogen |
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Nuclear
Quadrupole Coupling Constants |
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in 1,2,4-Thiadiazole |
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Calculation
of the
nitrogen nqcc's in 1,2,4-Thiadiazole was
made on the substitution molecular structure of Stiefvater [1,2]. These
are given in Tables 1 and 2. Structure paameters are given in Table 3. |
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In Tables 1 and 2, 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. |
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RSD is the
calibration residual standard deviation of the B3PW91/6-311+G(df,pd)
model for calculation of nitrogen nqcc's. |
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Table 1. N(2) nqcc's in 1,2,4-Thiadiazole (MHz). Calculation was made
on the rs structure of Stiefvater [1,2]. |
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Calc. |
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Expt. |
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14N(2) |
Xaa |
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1.095 |
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Xbb |
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2.267 |
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Xcc |
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1.172 |
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|Xab| |
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2.944 |
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RSD |
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0.030 (1.3 %) |
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Xxx |
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2.805 |
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Xyy |
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1.172 |
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Xzz |
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3.977 |
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ETA |
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0.410 |
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Øz,a |
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59.86 |
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Øa,bi |
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74.79 |
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Øz,bi * |
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14.93 |
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* The z-axis makes an angle of 14.93o with the external bisector ('bi') of the SNC angle and tilts toward S(1). |
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Table 2. N(4) nqcc's in 1,2,4-Thiadiazole (MHz). Calculation was made
on the rs structure of Stiefvater [1,2]. |
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Calc. |
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Expt. |
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14N(4) |
Xaa |
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2.881 |
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Xbb |
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0.387 |
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Xcc |
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2.494 |
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|Xab| |
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2.373 |
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RSD |
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0.030 (1.3 %) |
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Xxx |
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1.634 |
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Xyy |
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2.494 |
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Xzz |
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4.128 |
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ETA |
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0.208 |
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Øz,a |
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27.72 |
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Øa,bi |
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27.25 |
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Øz,bi * |
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0.47 |
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* The z-axis makes an angle of 0.47o with the external bisector ('bi') of the CNC angle and tilts toward C(5). |
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| Table 3. 1,2,4-Thiadiazole. Molecular structure parameters, rs [1,2] (Å
and degrees). |
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S(1)N(2) |
1.6492(10) |
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N(2)C(3) |
1.3165(10) |
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C(3)N(4) |
1.3665(15) |
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N(4)C(5) |
1.3135(15) |
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C(5)S(1) |
1.7073(15) |
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C(5)H(5) |
1.0784(10) |
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C(3)H(3) |
1.0780(20) |
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C(5)S(1)N(2) |
92.76(10) |
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S(1)N(2)C(3) |
107.09(5) |
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N(2)C(3)N(4) |
120.13(10) |
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C(3)N(4)C(5) |
107.73(5) |
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N(4)C(5)S(1) |
112.30(5) |
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S(1)C(5)H(5) |
123.90(5) |
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N(4)C(3)H(3) |
119.94(20) |
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[1] O.L.Stiefvater,
Z.Naturforsch. 31a,1681(1976). |
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[2]
Landolt-Börnstein, Numerical Data and Functional Relationships in
Science and Technology, New Series, ed. O.Madelung, Group II, Volume
15, Structure Data of Free Polyatomic Molecules, eds: K.-H.Hellwege and
A.M.Hellwege, Springer-Verlag, Berlin. |
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Thiazole |
1,3,4-Oxadiazole |
1,2,5-Oxadiazole |
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1,2,3-Thiadiazole |
1,2,5-Thiadiazole |
1,3,4-Thiadiazole |
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Table of Contents |
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Molecules/Nitrogen |
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124TDZ.html |
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Last
Modified 24 May 2003 |
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