Achieve Week 9 - #1

[BB Dis 1H]

Give the systematic name of this coordination compound. --> [Co(NH3)5Cl]Cl2
The answer is pentaamminechlorocobalt (III) chloride. How come for the Cl2 at the end it is chloride and not dichloride?

[Joshua Lance Yumul 1F]

Hey! the answer at the end is chloride because the complex ion on the left is worth a 2+ charge, and the counter ion of cl is worth 2-. It is like the same idea for chemical formulas like Mgf2 where the formula would be written out as magnesium fluoride.

[Anna Dai-Liu 3B]

I think the Greek prefixes only apply to elements within the coordination sphere (inside the brackets), but not to anything else (such as the chlorine atoms, which are separate).

[705573518]

The prefixes are only used for the ligands attached to the TM. No need to put di- in front of chloride as long as it is outside the brackets.

[Saebean Yi 3E]

It's "chloride" because we read the Cl on the outside of the brackets (because this Cl isn't a ligand) as we normally would. For example, a molecule like BeCl2, we would read it as beryllium chloride, not dichloride.

[Zoe Dhalla 3I]

The prefixes are only applied to ligands attached to the elements inside of the brackets, so you don't need to put the di- in front of chloride.

[Omeed Kalan]

That is because the prefixes only apply to the TM. Also chloride is a diatomic molecule

[Shaleena 3C]

Im pretty sure because chloride is read normally outside of the brackets rights? You'd only use dichloride if it's inside them. I could be wrong though.

[505739628]

Hi! I believe for anions at the end, it isn't necessary to include the prefix because if you know everything else, you would be able to solve for how many are in the compound based on charge and what would make the compound have a net charge of zero (or whatever the net charge of it is if it happens to have one). When I was doing the book problems, I just solved for a net charge of zero so I would assume that usually if we are just given the name and told to find the formula we would assume there is a net charge of zero and that's why we don't need prefixed for the cations and anions.

[Olivia Ghorai 1J]

Hi,

So the greek prefixes are only used in naming the coordination complex. While the Cl2 is given to you, note that it is not inside the square brackets [ ]. This means that it is not a part of the coordination complex, it is just interacting with the coordination complex.

[Jessica Cornelia Hongarta 1G]

Hi! So, use the mono, di, tri, etc. when you name whatever is in the coordination sphere, for the ligands that form coordination covalent bond with the central metal atom. However, for whatever is outside the bracket, in this case Cl, you do not use mono, di, tri, etc.. Name it like you would name an ionic compound, MgCl2 will be magnesium chloride instead of magnesium dichloride.