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	hartrees
Energy at 0K	-152.768859
Energy at 298.15K	-152.771853
HF Energy	-152.768859
Nuclear repulsion energy	97.738987

Mode Number	Symmetry	Frequency (cm^-1)	Scaled Frequency (cm^-1)	IR Intensities (km mol^-1)
1	A_g	3509	3131	0.00
2	A_g	1747	1559	0.00
3	A_g	1221	1090	0.00
4	A_g	1032	921	0.00
5	A_u	917	818	0.00
6	A_u	565	504	0.00
7	B_1g	939	838	0.00
8	B_1u	3491	3116	0.81
9	B_1u	1765	1575	0.22
10	B_1u	1117	997	3.66
11	B_2g	675	603	0.00
12	B_2u	3456	3084	21.89
13	B_2u	1365	1218	33.60
14	B_2u	803	717	0.90
15	B_3g	3435	3065	0.00
16	B_3g	1247	1113	0.00
17	B_3g	930	830	0.00
18	B_3u	647	578	64.00

Atom	y (Å)	z (Å)
C1	0.672	0.798
C2	0.672	-0.798
C3	-0.672	0.798
C4	-0.672	-0.798
H5	1.460	1.562
H6	1.460	-1.562
H7	-1.460	1.562
H8	-1.460	-1.562

	C1	C2	C3	C4	H5	H6	H7	H8
C1		1.5958	1.3432	2.0858	1.0974	2.4876	2.2640	3.1796
C2	1.5958		2.0858	1.3432	2.4876	1.0974	3.1796	2.2640
C3	1.3432	2.0858		1.5958	2.2640	3.1796	1.0974	2.4876
C4	2.0858	1.3432	1.5958		3.1796	2.2640	2.4876	1.0974
H5	1.0974	2.4876	2.2640	3.1796		3.1232	2.9194	4.2752
H6	2.4876	1.0974	3.1796	2.2640	3.1232		4.2752	2.9194
H7	2.2640	3.1796	1.0974	2.4876	2.9194	4.2752		3.1232
H8	3.1796	2.2640	2.4876	1.0974	4.2752	2.9194	3.1232

atom1	atom2	atom3	angle	atom1	atom2	atom3	angle
C1	C2	C4	90.000	C1	C2	H6	134.101
C1	C3	C4	90.000	C1	C3	H7	135.899
C2	C1	C3	90.000	C2	C1	H5	134.101
C2	C4	C3	90.000	C3	C1	H5	135.899
C4	C2	H6	135.899	C4	C3	H7	134.101

All results from a given calculation for C₄H₄ (cyclobutadiene)

using model chemistry: B3LYP/STO-3G

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	-0.080
2	C	-0.080
3	C	-0.080
4	C	-0.080
5	H	0.080
6	H	0.080
7	H	0.080
8	H	0.080

<r²>	57.702
(<r²>)^1/2	7.596

All results from a given calculation for C4H4 (cyclobutadiene)

using model chemistry: B3LYP/STO-3G

States and conformations

All results from a given calculation for C₄H₄ (cyclobutadiene)