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	hartrees
Energy at 0K	-154.217444
Energy at 298.15K	-154.220402
HF Energy	-153.654535
Nuclear repulsion energy	98.691716

Mode Number	Symmetry	Frequency (cm^-1)	Scaled Frequency (cm^-1)	IR Intensities (km mol^-1)
1	A_g	3334	3141	0.00
2	A_g	1622	1528	0.00
3	A_g	1156	1089	0.00
4	A_g	983	926	0.00
5	A_u	734	692	0.00
6	A_u	483	455	0.00
7	B_1g	831	783	0.00
8	B_1u	3322	3131	19.68
9	B_1u	1649	1554	6.47
10	B_1u	1084	1021	0.33
11	B_2g	528	498	0.00
12	B_2u	3302	3112	12.23
13	B_2u	1314	1238	30.41
14	B_2u	761	717	7.42
15	B_3g	3290	3100	0.00
16	B_3g	1227	1156	0.00
17	B_3g	893	841	0.00
18	B_3u	585	551	162.93

Atom	y (Å)	z (Å)
C1	0.672	0.784
C2	0.672	-0.784
C3	-0.672	0.784
C4	-0.672	-0.784
H5	1.438	1.544
H6	1.438	-1.544
H7	-1.438	1.544
H8	-1.438	-1.544

	C1	C2	C3	C4	H5	H6	H7	H8
C1		1.5685	1.3444	2.0658	1.0789	2.4512	2.2429	3.1425
C2	1.5685		2.0658	1.3444	2.4512	1.0789	3.1425	2.2429
C3	1.3444	2.0658		1.5685	2.2429	3.1425	1.0789	2.4512
C4	2.0658	1.3444	1.5685		3.1425	2.2429	2.4512	1.0789
H5	1.0789	2.4512	2.2429	3.1425		3.0886	2.8760	4.2203
H6	2.4512	1.0789	3.1425	2.2429	3.0886		4.2203	2.8760
H7	2.2429	3.1425	1.0789	2.4512	2.8760	4.2203		3.0886
H8	3.1425	2.2429	2.4512	1.0789	4.2203	2.8760	3.0886

atom1	atom2	atom3	angle	atom1	atom2	atom3	angle
C1	C2	C4	90.000	C1	C2	H6	134.784
C1	C3	C4	90.000	C1	C3	H7	135.216
C2	C1	C3	90.000	C2	C1	H5	134.784
C2	C4	C3	90.000	C3	C1	H5	135.216
C4	C2	H6	135.216	C4	C3	H7	134.784

All results from a given calculation for C₄H₄ (cyclobutadiene)

using model chemistry: CCD/6-31+G**

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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All results from a given calculation for C4H4 (cyclobutadiene)

using model chemistry: CCD/6-31+G**

States and conformations

All results from a given calculation for C₄H₄ (cyclobutadiene)