Name this Inorganic Complex Watch

Smoke_565
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K3[Co(CN)6]

I had tripotassium hexacyanocobalt(III) but when I googled it the formula comes up as tripotassium hexacyanocobaltate (III). Why is it cobaltate? The complex itself is neutral isn't it? 6 positive charges ( 1 from each K and Co has a 3+ charge otherwise the formula should have a negative sign outside the brackets) I thought it was neutral so the name doesn't change to 'ate' at the end? Any help please
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Goods
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(Original post by Smoke_565)
K3[Co(CN)6]

I had tripotassium hexacyanocobalt(III) but when I googled it the formula comes up as tripotassium hexacyanocobaltate (III). Why is it cobaltate? The complex itself is neutral isn't it? 6 positive charges ( 1 from each K and Co has a 3+ charge otherwise the formula should have a negative sign outside the brackets) I thought it was neutral so the name doesn't change to 'ate' at the end? Any help please
Exactly as the cyancolbaltate cancel out the positive charge of the potassium it must mean the compound as a whole is an ionic salt hence the suffix 'ate'


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Smoke_565
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So do you basically focus on what's inside the brackets for determining the charge when writing the name of your compound and ignore the counter ions? That is what is confusing me.
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charco
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(Original post by Smoke_565)
So do you basically focus on what's inside the brackets for determining the charge when writing the name of your compound and ignore the counter ions? That is what is confusing me.
Ionic compounds are named from the cation followed by the anion, When a metal atom is found in the anion it changes its name to identify its position. This doesn't just apply to transition metal complexes, but it's very common with them.

Iron becomes 'ferrate' etc. If there is any doubt about the oxidation state this is included as well.

Potassium hexacyanoferrate(III)
Potassium hexacyanoferrate(II)

etc.

Work out the formula from the name.

Hexa = 6 cyano groups (CN) each with a 1 negative charge
Ferrate(III) = iron with a 3+ charge
Overall then the ion has a 3 negative charge and will need 3 potassium ions to balance it.
K3[Fe(CN)6]
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Borek
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(Original post by Smoke_565)
The complex itself is neutral isn't it?
If the complex itself (cobalt and six CN-) were neutral it would not need three potassium cations as counterions. You mean "salt molecule" is neutral.
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