_P.-Powell-auth.-Principles-of-Organometallic-Chemistry-Springer-Netherlands-1988

"P
1·81 ---=
Be
@
Se-ring Plone
(o)
o
1.53 A
~
Mg
@
(b)
Distonces Co-C(~5) 2.80
Co-C (~3) 2.70, 2.79, 2.95
Co-C (~ 1 ) 3.10
(c)
~
M
1
Me
(d)
(e)
Me
1
Me
1
H~
~Hg~~
\::d "-H
( f)
tg)
Fig. 3.22 Structures of some cyclopentadienyl compounds of Group II elements.
(a) Cp 2 Be, a 'slip sandwich'; (b) Cp 2 Mg, a symmetrical sandwich;
( c) Environment of Ca in Cp 2 Ca; ( d) CpBeMe and CpZnMe(gl; ( e) Bridging methyl
groups in [CpMg(OEt,)],; (f) Bridging cyclic pentadienyl groups in MeZnCp 151 ;
(g) Cp,Hg, a fluxional '7'-Cp molecule.