National Institute of Standards and Technology
Computational Chemistry Comparison and Benchmark DataBase
Release 17bSeptember 2015
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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I.B.3. (II.A.2.)

All data (experiment and calculated) in the CCCBDB for C5H4O2 (4-Cyclopentene-1,3-dione)

Other names
2-Cyclopentene-1,4-dione; 2-cyclopenten-1,4-dione; 4-Cyclopenten-1,3-dione; Cyclopent-2-en-1,4-dione; cyclopent-2-ene-1,4-dione; cyclopent-4-ene-1,3-dione;

An "x" indicates that data is available. A number indicates how many calculations have been completed.
Property Experiment Calculated Comparison
Enthalpy 298.15K enthalpy of formation      
Enthalpy 0K enthalpy of formation      
Energy 0K   220  
Energy 298.15K   11  
Atomization Enthalpy 298.15K  8 
Atomization Enthalpy 0K  170 
Entropy (298.15K) entropy  0 
Entropy at any temperature   0  
Integrated Heat Capacity integrated heat capacity  0 
Heat Capacity (Cp) Heat capacity  0 
Nuclear Repulsion Energy   216  
HOMO-LUMO Energies HOMO energies   214  
Barriers to Internal Rotation internal rotation  0 
Geometries Cartesians  214  
Internal Coordinates bond lengths bond angles x214x
Products of moments of inertia moments of inertia  206 
Rotational Constants rotational constants  214 
Point Group  218 
Vibrations Vibrational Frequencies vibrations  6156 
Vibrational Intensities  226 
Zero-point energies  223 
Vibrational scaling factors  
Anharmonic frequencies and constants      
Electronic States Electronic states   0  
Electrostatics Atom charges   142  
Dipole dipole  144 
Quadrupole quadrupole  141 
Polarizability polarizability  145 
Other results Spin   0  
Number of basis functions   3  
Conformations   1  
2015 06 10 17:36