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	hartrees
Energy at 0K	-24.055671
Energy at 298.15K	-24.059081
HF Energy	-24.055671
Nuclear repulsion energy	50.235795

Mode Number	Symmetry	Frequency (cm^-1)	Scaled Frequency (cm^-1)	IR Intensities (km mol^-1)
1	A_g	3419	3120	0.00
2	A_g	1702	1553	0.00
3	A_g	1208	1103	0.00
4	A_g	1028	938	0.00
5	A_u	986	900	0.00
6	A_u	587	535	0.00
7	B_1g	1005	917	0.00
8	B_1u	3403	3105	27.31
9	B_1u	1709	1559	13.48
10	B_1u	1147	1046	1.54
11	B_2g	747	682	0.00
12	B_2u	3377	3082	9.56
13	B_2u	1385	1264	41.58
14	B_2u	785	716	14.41
15	B_3g	3359	3065	0.00
16	B_3g	1287	1174	0.00
17	B_3g	970	885	0.00
18	B_3u	713	651	263.49

Atom	y (Å)	z (Å)
C1	0.671	0.792
C2	0.671	-0.792
C3	-0.671	0.792
C4	-0.671	-0.792
H5	1.434	1.545
H6	1.434	-1.545
H7	-1.434	1.545
H8	-1.434	-1.545

	C1	C2	C3	C4	H5	H6	H7	H8
C1		1.5846	1.3427	2.0770	1.0716	2.4588	2.2358	3.1459
C2	1.5846		2.0770	1.3427	2.4588	1.0716	3.1459	2.2358
C3	1.3427	2.0770		1.5846	2.2358	3.1459	1.0716	2.4588
C4	2.0770	1.3427	1.5846		3.1459	2.2358	2.4588	1.0716
H5	1.0716	2.4588	2.2358	3.1459		3.0907	2.8677	4.2161
H6	2.4588	1.0716	3.1459	2.2358	3.0907		4.2161	2.8677
H7	2.2358	3.1459	1.0716	2.4588	2.8677	4.2161		3.0907
H8	3.1459	2.2358	2.4588	1.0716	4.2161	2.8677	3.0907

atom1	atom2	atom3	angle	atom1	atom2	atom3	angle
C1	C2	C4	90.000	C1	C2	H6	134.644
C1	C3	C4	90.000	C1	C3	H7	135.356
C2	C1	C3	90.000	C2	C1	H5	134.644
C2	C4	C3	90.000	C3	C1	H5	135.356
C4	C2	H6	135.356	C4	C3	H7	134.644

All results from a given calculation for C₄H₄ (cyclobutadiene)

using model chemistry: HF/CEP-121G

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	-0.218
2	C	-0.218
3	C	-0.218
4	C	-0.218
5	H	0.218
6	H	0.218
7	H	0.218
8	H	0.218

<r²>	49.851
(<r²>)^1/2	7.061

All results from a given calculation for C4H4 (cyclobutadiene)

using model chemistry: HF/CEP-121G

States and conformations

All results from a given calculation for C₄H₄ (cyclobutadiene)