The coordination number of Th in K₄[Th(C₂O₄)₄(OH₂)₂] is :
(C₂O$${_4^{2 - }}$$ = Oxalato)

The number of bridging CO ligand(s) and Co-Co bond(s) in Co₂(CO)₈, respectively are :

Match the metals (column I) with the coordination compound(s)/enzyme(s) (column II)

(Column I) Metals		(Column II) Coordination compounds(s) enzyme(s)
(A)	Co	(i)	Wilkinson catalyst
(B)	Zn	(ii)	Chlorophyl
(C)	Rh	(iii)	Vitamin B12
(D)	Mg	(iv)	Carbonic anhydrase

The difference in the number of unpaired electrons of a metal ion in its high spin and low-spin octahedral complexes is two. The metal ion is :