K3[V(C2O4)3] coordination and oxidation number

Question

K3[V(C2O4)3]

What is the coordination numer of this?

and this:

K2[MoOCl4]

3 and 5???

Answer 1

K3[V(C2O4)3]

[V(C2O4)3] has three potassium attached, they have an oxidation # of +1 each, three of them add up to +3,... so this means that [V(C2O4)3] must add up to -3

Vanadium has has three oxalates attached at -2 each, for a total of -6,... so for [V(C2O4)3] to add up to -3,... the vanadium must hav an oxidation number of +3

since oxalates are bidentate ligands, attaching twice each to the vanadium, three oxalates attach a total of 6 times to vanadium,...

so vanadium's coordination number is 6

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K2[MoOCl4] with two K+1 's attached, it means that [MoOCl4] must add up to a -2

[MoOCl4] has four chlorides @ -1 each & one oxide @ -2 , which adds up to -6 ,.. in order for the  [MoOCl4] to total -2,... the Mo must have an oxidation number of +4

the oxide & each of the four chlorides are monodentate ligands, so that 's five attachments,... which means that Mo has a coordination # of 5

so you are right on the Mo