Computational Chemistry Comparison and Benchmark DataBase Release 22 (May 2022) Standard Reference Database 101 National Institute of Standards and Technology
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All data (experiment and calculated) in the CCCBDB for C₅H₄O₂ (4-Cyclopentene-1,3-dione)

Property		Experiment	Calculated	Comparison
Energies Entropies	Enthalpy 298.15K
	Enthalpy 0K
	Energy 0K		242
	Energy 298.15K		227
	Atomization Enthalpy 298.15K		8
	Atomization Enthalpy 0K		170
	Entropy (298.15K)		0
	Entropy at any temperature		0
	Integrated Heat Capacity		0
	Heat Capacity (Cp)		0
	Nuclear Repulsion Energy		237
	HOMO-LUMO Energies		237
	Barriers to Internal Rotation		0
Geometries	Cartesians		237
	Internal Coordinates	x	236	x
	Products of moments of inertia		228
	Rotational Constants		237
	Point Group		241
Vibrations	Vibrational Frequencies		240
	Vibrational Intensities		243
	Zero-point energies		240
	Vibrational scaling factors
	Anharmonic frequencies and constants
	Raman frequencies and intensities		5
Electronic States	Electronic states	x	0
Electrostatics	Atom charges		163
	Dipole		165
	Quadrupole		160
	Polarizability		168
Other results	Spin		0
	Number of basis functions		3
	Conformations		1