Editing Group 12 element (section)

===Compounds===
{{see also|Compounds of zinc|Organozinc compounds|Organocadmium compound|Organomercury}}
All three metal ions form many [[Tetrahedral molecular geometry|tetrahedral]] species, such as {{chem|MCl|4|2-}}. Both zinc and cadmium can also form octahedral complexes such as the [[Metal ions in aqueous solution|aqua ions]] [M(H<sub>2</sub>O)<sub>6</sub>]<sup>2+</sup> which are present in aqueous solutions of salts of these metals.<ref>{{cite book |last= Richens |first= David T. |title=The Chemistry of Aqua Ions |publisher=J. Wiley  |date=September 1997 |isbn= 978-0-471-97058-3}}</ref> Covalent character is achieved by using the s and p orbitals. Mercury, however, rarely exceeds a [[coordination number]] of four. Coordination numbers of 2, 3, 5, 7 and 8 are also known.