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	hartrees
Energy at 0K	-154.734985
Energy at 298.15K	-154.738064
HF Energy	-154.734985
Nuclear repulsion energy	99.004189

Mode Number	Symmetry	Frequency (cm^-1)	Scaled Frequency (cm^-1)	IR Intensities (km mol^-1)
1	A_g	3242	3134	0.00
2	A_g	1628	1573	0.00
3	A_g	1112	1074	0.00
4	A_g	952	920	0.00
5	A_u	891	861	0.00
6	A_u	541	522	0.00
7	B_1g	889	860	0.00
8	B_1u	3232	3124	20.87
9	B_1u	1634	1580	4.53
10	B_1u	1060	1025	0.10
11	B_2g	605	585	0.00
12	B_2u	3210	3103	12.89
13	B_2u	1264	1222	39.02
14	B_2u	698	674	9.37
15	B_3g	3195	3088	0.00
16	B_3g	1193	1153	0.00
17	B_3g	852	824	0.00
18	B_3u	587	567	127.13

Atom	y (Å)	z (Å)
C1	0.664	0.788
C2	0.664	-0.788
C3	-0.664	0.788
C4	-0.664	-0.788
H5	1.429	1.549
H6	1.429	-1.549
H7	-1.429	1.549
H8	-1.429	-1.549

	C1	C2	C3	C4	H5	H6	H7	H8
C1		1.5753	1.3286	2.0608	1.0788	2.4584	2.2272	3.1369
C2	1.5753		2.0608	1.3286	2.4584	1.0788	3.1369	2.2272
C3	1.3286	2.0608		1.5753	2.2272	3.1369	1.0788	2.4584
C4	2.0608	1.3286	1.5753		3.1369	2.2272	2.4584	1.0788
H5	1.0788	2.4584	2.2272	3.1369		3.0977	2.8575	4.2144
H6	2.4584	1.0788	3.1369	2.2272	3.0977		4.2144	2.8575
H7	2.2272	3.1369	1.0788	2.4584	2.8575	4.2144		3.0977
H8	3.1369	2.2272	2.4584	1.0788	4.2144	2.8575	3.0977

atom1	atom2	atom3	angle	atom1	atom2	atom3	angle
C1	C2	C4	90.000	C1	C2	H6	134.878
C1	C3	C4	90.000	C1	C3	H7	135.122
C2	C1	C3	90.000	C2	C1	H5	134.878
C2	C4	C3	90.000	C3	C1	H5	135.122
C4	C2	H6	135.122	C4	C3	H7	134.878

All results from a given calculation for C₄H₄ (cyclobutadiene)

using model chemistry: B3LYP/cc-pVTZ

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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Number	Element	Mulliken
1	C	-0.119
2	C	-0.119
3	C	-0.119
4	C	-0.119
5	H	0.119
6	H	0.119
7	H	0.119
8	H	0.119

<r²>	57.826
(<r²>)^1/2	7.604

All results from a given calculation for C4H4 (cyclobutadiene)

using model chemistry: B3LYP/cc-pVTZ

States and conformations

All results from a given calculation for C₄H₄ (cyclobutadiene)