In $K_4[Fe(CN)_6]$,the primary valency of iron is .........

Which of the following compounds is a zero-valent metal complex?

How many ions are produced in aqueous solution of $[Co(H_2O)_6]Cl_2$?

Which of the following coordination complexes contains a neutral ligand?

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

How many water molecules are hydrogen bonded in the following molecular formula $[Cu(H_{2}O)_{4}]^{2+} SO_{4}^{2-} \cdot H_{2}O$?