What is the coordination number of cobalt in $[Co(NH_3)_4Cl_2]Cl$?

$A$ $200 \ mL$ solution $X$ contains $0.02 \ mol$ of $[Co(NH_3)_5Br]Cl_2$ and $0.02 \ mol$ of $[Co(NH_3)_5Cl]SO_4$. If solution $X$ is treated with excess $AgNO_3$ and excess $BaCl_2$,what will be the number of moles of precipitates $Y$ and $Z$ formed,respectively?

In complex compounds,the metal-ligand bond is:

Ammonia acts as a ligand but ammonium ion does not form complexes because

How many $EDTA$ molecules are required to form an octahedral complex with a $Ca^{2+}$ ion?

Number of ambidentate ligands in a representative metal complex $[M(en)(SCN)_4]$ is $[en = \text{ethylenediamine}]$