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	hartrees
Energy at 0K	-154.566761
Energy at 298.15K	-154.569719
HF Energy	-154.566761
Nuclear repulsion energy	97.290510

Mode Number	Symmetry	Frequency (cm^-1)	Scaled Frequency (cm^-1)	IR Intensities (km mol^-1)
1	A_g	3206	3181	0.00
2	A_g	1569	1557	0.00
3	A_g	1082	1074	0.00
4	A_g	917	910	0.00
5	A_u	856	850	0.00
6	A_u	527	523	0.00
7	B_1g	823	817	0.00
8	B_1u	3189	3165	42.32
9	B_1u	1568	1556	3.56
10	B_1u	1049	1041	0.16
11	B_2g	599	595	0.00
12	B_2u	3166	3142	20.55
13	B_2u	1235	1225	33.46
14	B_2u	629	624	5.49
15	B_3g	3150	3126	0.00
16	B_3g	1165	1156	0.00
17	B_3g	842	836	0.00
18	B_3u	589	584	135.71

Atom	y (Å)	z (Å)
C1	0.677	0.804
C2	0.677	-0.804
C3	-0.677	0.804
C4	-0.677	-0.804
H5	1.454	1.567
H6	1.454	-1.567
H7	-1.454	1.567
H8	-1.454	-1.567

	C1	C2	C3	C4	H5	H6	H7	H8
C1		1.6071	1.3536	2.1012	1.0889	2.4941	2.2630	3.1869
C2	1.6071		2.1012	1.3536	2.4941	1.0889	3.1869	2.2630
C3	1.3536	2.1012		1.6071	2.2630	3.1869	1.0889	2.4941
C4	2.1012	1.3536	1.6071		3.1869	2.2630	2.4941	1.0889
H5	1.0889	2.4941	2.2630	3.1869		3.1331	2.9073	4.2742
H6	2.4941	1.0889	3.1869	2.2630	3.1331		4.2742	2.9073
H7	2.2630	3.1869	1.0889	2.4941	2.9073	4.2742		3.1331
H8	3.1869	2.2630	2.4941	1.0889	4.2742	2.9073	3.1331

atom1	atom2	atom3	angle	atom1	atom2	atom3	angle
C1	C2	C4	90.000	C1	C2	H6	134.485
C1	C3	C4	90.000	C1	C3	H7	135.515
C2	C1	C3	90.000	C2	C1	H5	134.485
C2	C4	C3	90.000	C3	C1	H5	135.515
C4	C2	H6	135.515	C4	C3	H7	134.485

All results from a given calculation for C₄H₄ (cyclobutadiene)

using model chemistry: BLYP/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	-0.112
2	C	-0.112
3	C	-0.112
4	C	-0.112
5	H	0.112
6	H	0.112
7	H	0.112
8	H	0.112

<r²>	59.095
(<r²>)^1/2	7.687

All results from a given calculation for C4H4 (cyclobutadiene)

using model chemistry: BLYP/6-31G

States and conformations

All results from a given calculation for C₄H₄ (cyclobutadiene)