National Institute of Standards and Technology
Computational Chemistry Comparison and Benchmark DataBase
Release 19April 2018
NIST Standard Reference Database 101
IIExperimental data
IIICalculated data
IVData comparisons
VCost comparisons
VIInput and output files
VIITutorials and Units
VIIILinks to other sites
XOlder CCCBDB versions
XIII Vibrations
XIVReaction data
XVEntropy data
XVIBibliographic data
XVIIIon data
XVIIIBad calculations
XIXIndex of properties
XXH-bond dimers

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II.A.3. (XII.A.1.)

Listing of experimental geometry data for CH2- (methylene anion)

Rotational Constants (cm-1)

See section I.F.4 to change rotational constant units
73.05775 8.41517 7.21927
Rotational Constants from 1982Sea/Bun:5348
Calculated rotational constants for CH2- (methylene anion).

Point Group D∞h

Internal coordinates

(distances (r) in Å) (angles (a) in degrees) (dihedrals (d) in degrees)
Description Value Connectivity Reference Comment
Atom 1 Atom 2 Atom 3 Atom 4
rCH 1.085 1 2 1998Kuc r0 value
aHCH 135.5 2 1 3 1998Kuc a0 value
picture of methylene anion

Bond descriptions

Examples: C-C single bond, C=C, double bond, C#C triple bond, C:C aromatic bond
Bond Type Count
H-C 2

Atom x (Å) y (Å) z (Å)
C1 0.0000 0.0000 0.1027
H2 0.0000 1.0042 -0.3081
H3 0.0000 -1.0042 -0.3081

Atom - Atom Distances (Å)

  C1 H2 H3

Calculated geometries for CH2- (methylene anion).
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squib reference DOI
1982Sea/Bun:5348 Sears, T.J.; Jennings, D.A.; Brown, J.M. "The rotational spectrum and hyperfine structure of the methylene radical CH2 studied by far-infrared laser magnetic resonance spectroscopy." Journal of Chemical Physics. 77, 5348-5362 (1982) 10.1063/1.443783
1998Kuc K Kuchitsu(ed) "Structure of Free Polyatomic Molecules - Basic Data" Springer, Berlin, 1998 10.1007/978-3-642-45748-7 

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