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	hartrees
Energy at 0K	-154.634641
Energy at 298.15K	-154.637750
HF Energy	-154.634641
Nuclear repulsion energy	98.110361

Mode Number	Symmetry	Frequency (cm^-1)	Scaled Frequency (cm^-1)	IR Intensities (km mol^-1)
1	A_g	3296	3171	0.00
2	A_g	1629	1567	0.00
3	A_g	1121	1079	0.00
4	A_g	955	919	0.00
5	A_u	908	874	0.00
6	A_u	549	528	0.00
7	B_1g	882	848	0.00
8	B_1u	3281	3156	29.61
9	B_1u	1631	1569	2.98
10	B_1u	1081	1040	0.50
11	B_2g	639	615	0.00
12	B_2u	3257	3134	11.96
13	B_2u	1278	1229	35.29
14	B_2u	677	651	6.95
15	B_3g	3241	3118	0.00
16	B_3g	1210	1164	0.00
17	B_3g	876	843	0.00
18	B_3u	623	599	156.63

Atom	y (Å)	z (Å)
C1	0.672	0.796
C2	0.672	-0.796
C3	-0.672	0.796
C4	-0.672	-0.796
H5	1.442	1.554
H6	1.442	-1.554
H7	-1.442	1.554
H8	-1.442	-1.554

	C1	C2	C3	C4	H5	H6	H7	H8
C1		1.5915	1.3434	2.0827	1.0810	2.4731	2.2455	3.1607
C2	1.5915		2.0827	1.3434	2.4731	1.0810	3.1607	2.2455
C3	1.3434	2.0827		1.5915	2.2455	3.1607	1.0810	2.4731
C4	2.0827	1.3434	1.5915		3.1607	2.2455	2.4731	1.0810
H5	1.0810	2.4731	2.2455	3.1607		3.1088	2.8836	4.2402
H6	2.4731	1.0810	3.1607	2.2455	3.1088		4.2402	2.8836
H7	2.2455	3.1607	1.0810	2.4731	2.8836	4.2402		3.1088
H8	3.1607	2.2455	2.4731	1.0810	4.2402	2.8836	3.1088

atom1	atom2	atom3	angle	atom1	atom2	atom3	angle
C1	C2	C4	90.000	C1	C2	H6	134.571
C1	C3	C4	90.000	C1	C3	H7	135.429
C2	C1	C3	90.000	C2	C1	H5	134.571
C2	C4	C3	90.000	C3	C1	H5	135.429
C4	C2	H6	135.429	C4	C3	H7	134.571

All results from a given calculation for C₄H₄ (cyclobutadiene)

using model chemistry: B3LYP/6-31G

States and conformations

	Computational Chemistry Comparison and Benchmark DataBase Release 22 (May 2022) Standard Reference Database 101 National Institute of Standards and Technology
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Calc. vs exp. Bad Vib. HF vs MP2 Bad scale factors Low excited states Oddities NaCN Is not linear FAQ Help Units Choose Units Energy Bond length Rotational Constant Moment of Inertia Dipole and Quadrupole Polarizability Explanations Hartree cm-1 Debye Credits Just show me Show me a calculated geometry Summary Using older interface Limit Basis sets Method options List Recent molecules Choose a few Molecules Number of atoms By heavy atoms Diatomics InChI Deuterated Dimers Geometry Point group Point group count Bonds types Isodesmic reactions Bad point group Multiple conformers, states Vibrations Big anharmonicity Energy Enthalpy at 0 Kelvin Similar molecules Similar Isomers Cis/trans Tautomers Multiple conformers, states Ions, Dipoles, etc. List Ions Ionization changes point group Dipole Quadrupole Polarizability Proton Affinities Index of CCCBDB Feedback Error form Wants
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Number	Element	Mulliken
1	C	-0.142
2	C	-0.142
3	C	-0.142
4	C	-0.142
5	H	0.142
6	H	0.142
7	H	0.142
8	H	0.142

<r²>	58.304
(<r²>)^1/2	7.636

All results from a given calculation for C4H4 (cyclobutadiene)

using model chemistry: B3LYP/6-31G

States and conformations

All results from a given calculation for C₄H₄ (cyclobutadiene)