Coordination Sphere

[Jessica Helfond 2F]

What does it mean if something is outside of the coordination sphere? How does that work structurally?

[Albert Duong 4C]

If you look at coordination compounds such as [Co(NH3)6]Cl3 and [NiCl2(NH3)4]2H2O, basically anything outside of the brackets is considered outside of the coordination sphere. Structurally, the outside molecules or ions form bonds (some are more ionic in character such as the Cl- ions and some more covalent like with the H2O molecules). Here is what [Co(NH3)6]Cl3 looks like in 3D:

[Madeline Motamedi 4I]

For clarification, look at the second picture of the above reply. As you can tell, there is a central atom with other molecules attached and branching outwards from there. The initial bonds coming from the central atom create your coordination sphere. Everything else branching out form that initial circle of atoms is outside of the coordination sphere. All the light grey small atoms attached to the blue spheres as well as the the green spheres are outside of the coordination sphere.

[Nell Mitchell 1E]

Atoms or molecules that are not attached to the central atom of the coordination compound are outside of the coordination sphere. When written out in formula, anything outside the brackets is outside the coordination sphere.

[taryn_baldus2E]

Atoms that are outside of the coordination sphere are not directly attached to the central atom.