C5H6   -   Cyclopentadiene

Molecular constants for cyclopentadiene

Parameter Value Ref.
Rotational Constants
A″ [MHz] 6426.1205(69) a
B″ [MHz] 8225.6602(12)
C″ [MHz] 4271.4441(31)
τ1 [MHz] -0.02703(603)
τ2 [MHz] -0.00822(203)
τ3 [MHz] 1.37(20) b
τaaaa [MHz] -0.01347(199)
τbbbb [MHz] -0.01484(228)
Dipole Moment
µb [C · m]
    µb [D]
1.398(13) x 10-30
    0.419(4)
65030
Magnetic Constants
gaa -0.0700(3) µN 70065
gbb -0.0827(3) µN
gcc 0.0385(2) µN
2χaa - χbb - χcc +30.7(3) x 10-6 erg/(G2 · mol)
2χbb - χaa - χcc +37.8(3) x 10-6 erg/(G2 · mol)
Qaa 1.4(4) x 10-26 esu · cm2
Qbb 3.7.(4) x 10-26 esu · cm2
Qcc -5.1(5) x 10-26 esu · cm2
 
a J. Phys. Chem. Ref. Data 18(3), 1245-1524 (1989).
 
b Value determined by setting R6 = 0.

 

 

Rotational constants for 13C substituted cyclopentadiene

Parameter 13C1 a 13C2 13C3 Ref.
A [MHz] 8226.04(3) 8420.02(3) 8345.11(3) 65030
B [MHz] 8219.46(3) 8040.41(3) 8108.70(3)
C [MHz] 4217.76(3) 4119.40(3) 4119.07(3)
 
a Atom numbering is as follows: _C1H2C2H=C3HC4H=_C5H where C3 and C4 and C3 and C5 are equivalent.

 


 

C5H6   -   1-Penten-3-yne

Molecular constants for 1-penten-3-yne

Parameter CH2 = CHCCCH3 Ref.
A [GHz] 36.8(17) 71045
B [MHz] 2126.90(10)
C [MHz] 2026.32(10)
Dipole Moment
µa [C · m]
    µa [D]
1.905(7) x 10-30
    0.571(2)
71045
µb [C · m]
    µb [D]
1.11(15)  x 10-30
    0.334(41)

 


 

C5H6   -   Cyclopropylacetylene

Rotational constants and dipole moment for normal and deuterated cyclopropylacetylene

Parameter C3H5C ≡ CH Ref. C3H5C ≡ CD Ref.
A [MHz] 15 722.90(133) 8305172062 15 653.(63) 72062
B [MHz] 3360.006(4) 3139.67(2)
C [MHz] 3192.703(4) 2997.95(2)
µa [C · m]
    µa [D]
2.972(33) x 10-30
    0.891(10)
 
µc [C · m]
    µc [D]
0.160(33)  x 10-30
    0.048(10)

 

 

Rotational constants for 13C isotopic forms of cyclopropylacetylene

Isotopic Species A [MHz] B [MHz] C [MHz] Ref.
Rotational Constants
_CH2CH2_13CHCCH   (1 - 13C) 15 538.76(3604) 3350.53(2) 3190.99(2) 83051
_CH213CH_2CHCCH   (2 - 13C) 15 426.69(2363) 3319.58(2) 3146.32(2)
_CH2CH2_CH13CCH   (4 - 13C) 15681.92(2400) 3334.68(2) 3170.33(2)
_CH2CH2_CHC13CH   (5 - 13C) 15772.14(2171) 3254.22(2) 3097.90(1)

 


 

C5H6   -   2-Methyl-1-buten-3-yne

Molecular constants for 2-methyl-1-buten-3-yne

Parameter CH2C(CH3)CCH Ref.
Rotation-Internal Rotation Constants
A [MHz] 9359.699(32) a
B [MHz] 4013.514(20)
C [MHz] 2854.749(11)
ΔJK [kHz] 15.9(12)
δJ [kHz] 0.45(18)
δK [kHz] 5.9(30)
Iα (u Å2) 3.133 b
θ 59.2° b
V3 (cm-1) 2016.(40)
Electric Dipole Moment
µa [C · m]
    µa [D]
1.494(50)  x 10-30
    0.448(15)
69067
µb [C · m]
    µb [D]
0.827(33)  x 10-30
    0.248(10)
 
a J. Phys. Chem. Ref. Data 18(3), 1245-1524 (1989).
 
b Assumed value.

 


 

C5H6   -   cis-3-Penten-1-yne

Molecular constants for cis-3-penten-1-yne

Parameter CH3=CH=CHC≡CH Ref.
A [MHz] 11 792.088(63) a
B [MHz] 3388.222(18)
C [MHz] 2672.221(20)
ΔJ [MHz] 0.002 30(16)
ΔJK [MHz] -0.0132(12)
δJ [MHz] 0.000 88(27)
Internal Rotation Constants
Iα (u Å2) 3.16 (assumed)
θ 76.8(2)°
s 31.63
V3 (cm-1) 389.3(10)
 
a J. Phys. Chem. Ref. Data 18(3), 1245-1524 (1989).

 


 

C5H6   -   Bicyclo[2.1.0]pent-2-ene

Molecular constants for bicyclo[2.1.0]pent-2-ene

Parameter _$CHCHCH_CH$CH2 Ref.
Rotational Constants
A [MHz] 10 811.65(11) 70064
B [MHz] 6517.883(3)
C [MHz] 5216.287(3)
Dipole Moment
µa [C · m]
    µa [D]
1.378(3) x 10-30
    0.398(1)
µc [C · m]
    µc [D]
0.083(7) x 10-30
    0.025(2)
Zeeman Constants
gaa -0.0046(18) µN
gbb -0.0342(11) µN
gcc -0.0218(12) µN
2χaa - χbb - χcc -14.9(11) x 10-6 erg/(G2 · mol)
- χaa + 2χbb - χcc 7.8(15) x 10-6 erg/(G2 · mol)

 


 

C5H6   -   1,2,3-Pentatriene

Molecular constants for 1,2,3-pentatriene

Parameter CH2=C=C=CHCH3 Ref.
A [MHz] 29788.(20) a
B [MHz] 2212.987(5)
C [MHz] 2085.026(4)
DJ [kHz] 0.446(22)
DJK [kHz] -33.95(5)
Iα (u Å2) 3.10 (assumed)
θ 44.4° (assumed)
V3 (cm-1) 468.5(7)
Electric Dipole Moment
µa [C · m]
    µa [D]
1.67(17) x 10-30
    0.50(5)
87021
µb [C · m]
    µb [D]
0.407(10) x 10-30
    0.122(3)
 
a J. Phys. Chem. Ref. Data 18(3), 1245-1524 (1989).


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