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	hartrees
Energy at 0K	-154.628693
Energy at 298.15K	-154.631762
HF Energy	-154.628693
Nuclear repulsion energy	98.929443

Mode Number	Symmetry	Frequency (cm^-1)	Scaled Frequency (cm^-1)	IR Intensities (km mol^-1)
1	A_g	3265	3139	0.00
2	A_g	1647	1583	0.00
3	A_g	1120	1077	0.00
4	A_g	969	932	0.00
5	A_u	873	839	0.00
6	A_u	539	518	0.00
7	B_1g	850	817	0.00
8	B_1u	3253	3127	23.11
9	B_1u	1653	1589	2.43
10	B_1u	1065	1024	0.07
11	B_2g	609	586	0.00
12	B_2u	3229	3105	12.31
13	B_2u	1261	1212	36.35
14	B_2u	726	698	8.66
15	B_3g	3212	3088	0.00
16	B_3g	1167	1122	0.00
17	B_3g	837	805	0.00
18	B_3u	599	576	107.12

Atom	y (Å)	z (Å)
C1	0.666	0.786
C2	0.666	-0.786
C3	-0.666	0.786
C4	-0.666	-0.786
H5	1.437	1.545
H6	1.437	-1.545
H7	-1.437	1.545
H8	-1.437	-1.545

	C1	C2	C3	C4	H5	H6	H7	H8
C1		1.5727	1.3313	2.0606	1.0821	2.4561	2.2354	3.1398
C2	1.5727		2.0606	1.3313	2.4561	1.0821	3.1398	2.2354
C3	1.3313	2.0606		1.5727	2.2354	3.1398	1.0821	2.4561
C4	2.0606	1.3313	1.5727		3.1398	2.2354	2.4561	1.0821
H5	1.0821	2.4561	2.2354	3.1398		3.0909	2.8739	4.2205
H6	2.4561	1.0821	3.1398	2.2354	3.0909		4.2205	2.8739
H7	2.2354	3.1398	1.0821	2.4561	2.8739	4.2205		3.0909
H8	3.1398	2.2354	2.4561	1.0821	4.2205	2.8739	3.0909

atom1	atom2	atom3	angle	atom1	atom2	atom3	angle
C1	C2	C4	90.000	C1	C2	H6	134.543
C1	C3	C4	90.000	C1	C3	H7	135.457
C2	C1	C3	90.000	C2	C1	H5	134.543
C2	C4	C3	90.000	C3	C1	H5	135.457
C4	C2	H6	135.457	C4	C3	H7	134.543

All results from a given calculation for C₄H₄ (cyclobutadiene)

using model chemistry: B3PW91/6-31G(2df,p)

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	-0.137
2	C	-0.137
3	C	-0.137
4	C	-0.137
5	H	0.137
6	H	0.137
7	H	0.137
8	H	0.137

<r²>	57.347
(<r²>)^1/2	7.573

All results from a given calculation for C4H4 (cyclobutadiene)

using model chemistry: B3PW91/6-31G(2df,p)

States and conformations

All results from a given calculation for C₄H₄ (cyclobutadiene)