(i) \( [Co(en)_2ClBr]NO_3 \)
Step 1: This is a cationic complex with \(NO_3^-\) outside. Charge balance: complex \(= +1\); with two neutral 'en', one \(Cl^-\) and one \(Br^-\), cobalt must be \(+3\).
Step 2: List ligands alphabetically ignoring multiplying prefixes: bromido (b), chlorido (c), ethane-1,2-diamine (e). Since two 'en' are present and its name is complex, use 'bis'.
Step 3: Full name: bromidochloridobis(ethane-1,2-diamine)cobalt(III) nitrate.
(ii) \( [Ni(NH_3)_4][Pt(CN)_4] \)
Step 1: Two complex ions; cation named before anion. For \([Ni(NH_3)_4]^{2+}\), four neutral ammine ligands leave Ni at \(+2\).
Step 2: For \([Pt(CN)_4]^{2-}\), four cyanido ligands each \(-1\) make the ion \(-2\), so Pt is \(+2\); being the anion, platinum takes the '-ate' ending as platinate.
Step 3: Combined: tetraamminenickel(II) tetracyanidoplatinate(II).