A Computational and Structural Database Study of the Metal-Carbene Bond in Groups IA, IIA, and IIIA Imidazol-2-Ylidene Complexes

Table 2

The number of entries (hits), coordination number (CN), and bond parameters of group IIA metal-imidazol-2-ylidenes.

Metal	CN	No. of hits	D (M-Im) (Å)			Im-M-X angle (°)
			Mean	Range	St dev.	Mean	St dev.
Be	3	9	1.798	1.768–1.82	0.018	119.8	6.26
	4	2	1.811	1.8–1.822	0.016	108.9	4.99
	5	1 (MEHQIB)	1.765
Mg	3	8	2.25	2.204–2.288	0.025	115.5	5.17
	4	9	2.226	2.194–2.285	0.032	109.9	7.96
	5	2	2.246	2.226–2.279	0.029	107.6	6.68
Ca	3	2	2.613	2.598–2.628	0.021	117.5	1.98
	5	2	2.547	2.509–2.582	0.027	104.9	30.3
	6	8	2.606	2.518–2.705	0.058	96.6	25.32
	7	2	2.619	2.562–2.702	0.045	100.2	31.86