Textbook Question 9C.1

[Adam_Ventura_1H]

For part C of this question I am being asked to name this complex ion [CO(CN)5(OH2)]^2− . My question is on what the exact rule is on which ligand goes first in the name and when do we need to add the suffix -ate to the metal? Maybe someone could go step by step on how they named this complex ion. It would really help.

[Rose_Malki_3G]

List the ligands in alphabetical order and add the suffix -ate when the complex has a negative charge

[Giselle Granda 3F]

To break down this specific problem, you first determine the oxidation number of the cobalt in the complex, which turns out to be +3 because CN has a -1 charge, water is neutral, and the overall charge of the complex is -2, ( x+(-1)*5+0=-2 --> solve for x). Next you will list the ligands in alphabetical order, and the name of CN is cyano, while OH2 is aqua. Aqua comes first and since there is only one you leave it like that. Cyano comes next and since there is 5, you add the prefix penta- in front of it. Last comes cobalt, and you change the ending to -ate because the coordation complex has an overall negative charge. You must also add the roman numeral III after cobalate which is its oxidation number. If you put that all together the name is aquapentacyanocobalate (III) ion. Hope this is helpful!

[Immi Lee - 1D]

^^ Just for clarification because I personally got confused by this but there's a typo in the textbook and it's not CO but Co (Cobalt).