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	hartrees
Energy at 0K	-154.649667
Energy at 298.15K	-154.652773
HF Energy	-154.649667
Nuclear repulsion energy	97.605352

Mode Number	Symmetry	Frequency (cm^-1)	Scaled Frequency (cm^-1)	IR Intensities (km mol^-1)
1	A_g	3295	3167	0.00
2	A_g	1602	1540	0.00
3	A_g	1115	1071	0.00
4	A_g	965	928	0.00
5	A_u	900	866	0.00
6	A_u	538	517	0.00
7	B_1g	904	869	0.00
8	B_1u	3276	3149	27.21
9	B_1u	1598	1536	6.26
10	B_1u	1060	1019	4.11
11	B_2g	647	621	0.00
12	B_2u	3251	3125	8.28
13	B_2u	1259	1210	41.71
14	B_2u	693	667	12.31
15	B_3g	3235	3109	0.00
16	B_3g	1194	1148	0.00
17	B_3g	878	844	0.00
18	B_3u	630	605	240.15

Atom	y (Å)	z (Å)
C1	0.678	0.797
C2	0.678	-0.797
C3	-0.678	0.797
C4	-0.678	-0.797
H5	1.449	1.558
H6	1.449	-1.558
H7	-1.449	1.558
H8	-1.449	-1.558

	C1	C2	C3	C4	H5	H6	H7	H8
C1		1.5947	1.3565	2.0936	1.0830	2.4785	2.2592	3.1739
C2	1.5947		2.0936	1.3565	2.4785	1.0830	3.1739	2.2592
C3	1.3565	2.0936		1.5947	2.2592	3.1739	1.0830	2.4785
C4	2.0936	1.3565	1.5947		3.1739	2.2592	2.4785	1.0830
H5	1.0830	2.4785	2.2592	3.1739		3.1166	2.8978	4.2556
H6	2.4785	1.0830	3.1739	2.2592	3.1166		4.2556	2.8978
H7	2.2592	3.1739	1.0830	2.4785	2.8978	4.2556		3.1166
H8	3.1739	2.2592	2.4785	1.0830	4.2556	2.8978	3.1166

atom1	atom2	atom3	angle	atom1	atom2	atom3	angle
C1	C2	C4	90.000	C1	C2	H6	134.639
C1	C3	C4	90.000	C1	C3	H7	135.361
C2	C1	C3	90.000	C2	C1	H5	134.639
C2	C4	C3	90.000	C3	C1	H5	135.361
C4	C2	H6	135.361	C4	C3	H7	134.639

All results from a given calculation for C₄H₄ (cyclobutadiene)

using model chemistry: B3LYP/LANL2DZ

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	-0.250
2	C	-0.250
3	C	-0.250
4	C	-0.250
5	H	0.250
6	H	0.250
7	H	0.250
8	H	0.250

<r²>	58.797
(<r²>)^1/2	7.668

All results from a given calculation for C4H4 (cyclobutadiene)

using model chemistry: B3LYP/LANL2DZ

States and conformations

All results from a given calculation for C₄H₄ (cyclobutadiene)