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	hartrees
Energy at 0K	-153.575300
Energy at 298.15K	-153.578732
HF Energy	-153.575300
Nuclear repulsion energy	99.148673

Mode Number	Symmetry	Frequency (cm^-1)	Scaled Frequency (cm^-1)	IR Intensities (km mol^-1)
1	A_g	3473	3136	0.00
2	A_g	1762	1591	0.00
3	A_g	1216	1098	0.00
4	A_g	1018	919	0.00
5	A_u	1063	960	0.00
6	A_u	610	551	0.00
7	B_1g	1045	943	0.00
8	B_1u	3458	3122	19.89
9	B_1u	1773	1601	5.31
10	B_1u	1168	1054	0.40
11	B_2g	777	701	0.00
12	B_2u	3433	3099	5.80
13	B_2u	1401	1265	38.12
14	B_2u	754	681	12.16
15	B_3g	3416	3084	0.00
16	B_3g	1320	1192	0.00
17	B_3g	973	878	0.00
18	B_3u	730	659	227.16

Atom	y (Å)	z (Å)
C1	0.664	0.789
C2	0.664	-0.789
C3	-0.664	0.789
C4	-0.664	-0.789
H5	1.423	1.541
H6	1.423	-1.541
H7	-1.423	1.541
H8	-1.423	-1.541

	C1	C2	C3	C4	H5	H6	H7	H8
C1		1.5783	1.3274	2.0623	1.0680	2.4502	2.2176	3.1274
C2	1.5783		2.0623	1.3274	2.4502	1.0680	3.1274	2.2176
C3	1.3274	2.0623		1.5783	2.2176	3.1274	1.0680	2.4502
C4	2.0623	1.3274	1.5783		3.1274	2.2176	2.4502	1.0680
H5	1.0680	2.4502	2.2176	3.1274		3.0810	2.8454	4.1940
H6	2.4502	1.0680	3.1274	2.2176	3.0810		4.1940	2.8454
H7	2.2176	3.1274	1.0680	2.4502	2.8454	4.1940		3.0810
H8	3.1274	2.2176	2.4502	1.0680	4.1940	2.8454	3.0810

atom1	atom2	atom3	angle	atom1	atom2	atom3	angle
C1	C2	C4	90.000	C1	C2	H6	134.712
C1	C3	C4	90.000	C1	C3	H7	135.288
C2	C1	C3	90.000	C2	C1	H5	134.712
C2	C4	C3	90.000	C3	C1	H5	135.288
C4	C2	H6	135.288	C4	C3	H7	134.712

All results from a given calculation for C₄H₄ (cyclobutadiene)

using model chemistry: HF/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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Number	Element	Mulliken
1	C	-0.219
2	C	-0.219
3	C	-0.219
4	C	-0.219
5	H	0.219
6	H	0.219
7	H	0.219
8	H	0.219

<r²>	57.651
(<r²>)^1/2	7.593

All results from a given calculation for C4H4 (cyclobutadiene)

using model chemistry: HF/6-31G

States and conformations

All results from a given calculation for C₄H₄ (cyclobutadiene)