Table 2. Analysis of the electron density at the critical points between C atoms C2C3, C3C4 and C4C2.

Property	X-ray refinement	Gaussian wavefunction
C2C3
Bond length ()	1.5338(4)	1.5348
(r) (e 3)	1.48	1.54
Bond path ()	1.538	1.537
Bond-path angle () C4C2C3	67.69	67.27
Ellipticity,	0.609	0.529
2(r) (e 5)	4.589	2.875
1	10.157	10.679
2	6.31	6.99
3	11.88	7.39
C3C4
Bond distance ()	1.5019(4)	1.5016
(r) (e 3)	1.62	1.67
Bond path ()	1.506	1.504
Bond-path angle () C2C3C4	67.69	67.27
Ellipticity,	0.609	0.529
2(r) (e 5)	4.589	2.875
1	10.157	10.679
2	6.31	6.99
3	11.88	7.39
C4C2
Bond distance ()	1.5421(4)	1.54233
(r) (e 3)	1.46	1.51
Bond path ()	1.545	1.544
Bond-path angle () C3C4C2	63.85	63.38
Ellipticity,	0.67	0.57
2(r) (e 5)	3.94	2.74
1	9.96	10.53
2	5.95	6.69
3	11.97	7.43