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	hartrees
Energy at 0K	-154.600655
Energy at 298.15K	-154.603735
HF Energy	-154.600655
Nuclear repulsion energy	99.192758

Mode Number	Symmetry	Frequency (cm^-1)	Scaled Frequency (cm^-1)	IR Intensities (km mol^-1)
1	A_g	3295	3146	0.00
2	A_g	1677	1601	0.00
3	A_g	1139	1088	0.00
4	A_g	982	938	0.00
5	A_u	885	845	0.00
6	A_u	539	515	0.00
7	B_1g	863	824	0.00
8	B_1u	3284	3135	27.05
9	B_1u	1687	1611	2.62
10	B_1u	1073	1025	0.27
11	B_2g	598	571	0.00
12	B_2u	3262	3115	14.34
13	B_2u	1282	1224	35.02
14	B_2u	747	713	7.55
15	B_3g	3245	3098	0.00
16	B_3g	1190	1137	0.00
17	B_3g	836	798	0.00
18	B_3u	599	572	121.80

Atom	y (Å)	z (Å)
C1	0.665	0.782
C2	0.665	-0.782
C3	-0.665	0.782
C4	-0.665	-0.782
H5	1.435	1.543
H6	1.435	-1.543
H7	-1.435	1.543
H8	-1.435	-1.543

	C1	C2	C3	C4	H5	H6	H7	H8
C1		1.5649	1.3294	2.0534	1.0819	2.4492	2.2326	3.1325
C2	1.5649		2.0534	1.3294	2.4492	1.0819	3.1325	2.2326
C3	1.3294	2.0534		1.5649	2.2326	3.1325	1.0819	2.4492
C4	2.0534	1.3294	1.5649		3.1325	2.2326	2.4492	1.0819
H5	1.0819	2.4492	2.2326	3.1325		3.0852	2.8691	4.2131
H6	2.4492	1.0819	3.1325	2.2326	3.0852		4.2131	2.8691
H7	2.2326	3.1325	1.0819	2.4492	2.8691	4.2131		3.0852
H8	3.1325	2.2326	2.4492	1.0819	4.2131	2.8691	3.0852

atom1	atom2	atom3	angle	atom1	atom2	atom3	angle
C1	C2	C4	90.000	C1	C2	H6	134.637
C1	C3	C4	90.000	C1	C3	H7	135.363
C2	C1	C3	90.000	C2	C1	H5	134.637
C2	C4	C3	90.000	C3	C1	H5	135.363
C4	C2	H6	135.363	C4	C3	H7	134.637

All results from a given calculation for C₄H₄ (cyclobutadiene)

using model chemistry: B1B95/6-31G**

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	-0.160
2	C	-0.160
3	C	-0.160
4	C	-0.160
5	H	0.160
6	H	0.160
7	H	0.160
8	H	0.160

<r²>	57.147
(<r²>)^1/2	7.560

All results from a given calculation for C4H4 (cyclobutadiene)

using model chemistry: B1B95/6-31G**

States and conformations

All results from a given calculation for C₄H₄ (cyclobutadiene)