How the molecule dissociates and its geometry.

[going2breakdown]

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I've got a molecule here: Co(NH3)4Cl3 and it apparently breaks up into Co(NH3)4Cl2+ and Cl-. What is the rule for how a molecule will dissociate? (i.e. how do I know it was just one Cl that left the molecule?, they did tell me it dissociates into two ions, but how do I know the ions?) Also, it asks me the geometry, and I am supposed to use how many electron groups surround this to figure out the shape of the complex cation, so how do I figure this out without drawing out a Lewis structure, should I just try to do it in my head, or just assume they are all single bonds surrounding cobalt because it's an expanded valence shell?

 

[gettheleadout]

I've got a molecule here: Co(NH3)4Cl3 and it apparently breaks up into Co(NH3)4Cl2+ and Cl-. What is the rule for how a molecule will dissociate? (i.e. how do I know it was just one Cl that left the molecule?, they did tell me it dissociates into two ions, but how do I know the ions?) Also, it asks me the geometry, and I am supposed to use how many electron groups surround this to figure out the shape of the complex cation, so how do I figure this out without drawing out a Lewis structure, should I just try to do it in my head, or just assume they are all single bonds surrounding cobalt because it's an expanded valence shell?

I don't think there is any way to easily determine how the molecule will dissociate... At least in this case I don't and if there is I don't know it.

As for the geometry, since we have a complex cation and ammonia is monodentate (i.e. only the nitrogen atom has lone pairs) the bonds from NH3 ligands to the Co are indeed "single" bonds. Also be sure to use proper coordination compound representation; the dissociated products are ([Co(NH3)4]Cl2)+ and Cl-.

Hint: The chloride ligands within the complex are individual atoms, and thus must also be monodentate.