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	hartrees
Energy at 0K	-154.691638
Energy at 298.15K	-154.694684
HF Energy	-154.691638
Nuclear repulsion energy	98.597298

Mode Number	Symmetry	Frequency (cm^-1)	Scaled Frequency (cm^-1)	IR Intensities (km mol^-1)
1	A_g	3259	3143	0.00
2	A_g	1626	1568	0.00
3	A_g	1115	1075	0.00
4	A_g	959	925	0.00
5	A_u	875	843	0.00
6	A_u	532	513	0.00
7	B_1g	874	842	0.00
8	B_1u	3249	3133	21.67
9	B_1u	1637	1578	9.19
10	B_1u	1063	1025	0.62
11	B_2g	593	572	0.00
12	B_2u	3228	3113	11.97
13	B_2u	1265	1220	39.03
14	B_2u	710	684	8.42
15	B_3g	3213	3098	0.00
16	B_3g	1188	1146	0.00
17	B_3g	848	818	0.00
18	B_3u	588	567	164.33

Atom	y (Å)	z (Å)
C1	0.669	0.788
C2	0.669	-0.788
C3	-0.669	0.788
C4	-0.669	-0.788
H5	1.438	1.551
H6	1.438	-1.551
H7	-1.438	1.551
H8	-1.438	-1.551

	C1	C2	C3	C4	H5	H6	H7	H8
C1		1.5770	1.3381	2.0682	1.0833	2.4629	2.2411	3.1488
C2	1.5770		2.0682	1.3381	2.4629	1.0833	3.1488	2.2411
C3	1.3381	2.0682		1.5770	2.2411	3.1488	1.0833	2.4629
C4	2.0682	1.3381	1.5770		3.1488	2.2411	2.4629	1.0833
H5	1.0833	2.4629	2.2411	3.1488		3.1024	2.8766	4.2308
H6	2.4629	1.0833	3.1488	2.2411	3.1024		4.2308	2.8766
H7	2.2411	3.1488	1.0833	2.4629	2.8766	4.2308		3.1024
H8	3.1488	2.2411	2.4629	1.0833	4.2308	2.8766	3.1024

atom1	atom2	atom3	angle	atom1	atom2	atom3	angle
C1	C2	C4	90.000	C1	C2	H6	134.755
C1	C3	C4	90.000	C1	C3	H7	135.245
C2	C1	C3	90.000	C2	C1	H5	134.755
C2	C4	C3	90.000	C3	C1	H5	135.245
C4	C2	H6	135.245	C4	C3	H7	134.755

All results from a given calculation for C₄H₄ (cyclobutadiene)

using model chemistry: B3LYP/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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Number	Element	Mulliken
1	C	-0.133
2	C	-0.133
3	C	-0.133
4	C	-0.133
5	H	0.133
6	H	0.133
7	H	0.133
8	H	0.133

<r²>	58.385
(<r²>)^1/2	7.641

All results from a given calculation for C4H4 (cyclobutadiene)

using model chemistry: B3LYP/6-31+G**

States and conformations

All results from a given calculation for C₄H₄ (cyclobutadiene)