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	hartrees
Energy at 0K	-153.182192
Energy at 298.15K	-153.185036
HF Energy	-152.765996
Nuclear repulsion energy	96.501583

Mode Number	Symmetry	Frequency (cm^-1)	Scaled Frequency (cm^-1)
1	A_g	3245	3176
2	A_g	1500	1468
3	A_g	1103	1079
4	A_g	880	861
5	A_u	725	710
6	A_u	490	479
7	B_1g	805	787
8	B_1u	3228	3159
9	B_1u	1494	1463
10	B_1u	1053	1031
11	B_2g	550	538
12	B_2u	3206	3138
13	B_2u	1263	1236
14	B_2u	591	579
15	B_3g	3194	3126
16	B_3g	1195	1169
17	B_3g	892	873
18	B_3u	589	576

Atom	y (Å)	z (Å)
C1	0.682	0.816
C2	0.682	-0.816
C3	-0.682	0.816
C4	-0.682	-0.816
H5	1.454	1.576
H6	1.454	-1.576
H7	-1.454	1.576
H8	-1.454	-1.576

	C1	C2	C3	C4	H5	H6	H7	H8
C1		1.6312	1.3633	2.1259	1.0843	2.5136	2.2673	3.2068
C2	1.6312		2.1259	1.3633	2.5136	1.0843	3.2068	2.2673
C3	1.3633	2.1259		1.6312	2.2673	3.2068	1.0843	2.5136
C4	2.1259	1.3633	1.6312		3.2068	2.2673	2.5136	1.0843
H5	1.0843	2.5136	2.2673	3.2068		3.1528	2.9084	4.2894
H6	2.5136	1.0843	3.2068	2.2673	3.1528		4.2894	2.9084
H7	2.2673	3.2068	1.0843	2.5136	2.9084	4.2894		3.1528
H8	3.2068	2.2673	2.5136	1.0843	4.2894	2.9084	3.1528

atom1	atom2	atom3	angle	atom1	atom2	atom3	angle
C1	C2	C4	90.000	C1	C2	H6	134.562
C1	C3	C4	90.000	C1	C3	H7	135.438
C2	C1	C3	90.000	C2	C1	H5	134.562
C2	C4	C3	90.000	C3	C1	H5	135.438
C4	C2	H6	135.438	C4	C3	H7	134.562

All results from a given calculation for C₄H₄ (cyclobutadiene)

using model chemistry: MP4=FULL/3-21G

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: MP4=FULL/3-21G

States and conformations

All results from a given calculation for C₄H₄ (cyclobutadiene)