Using IUPAC norms

(a) Sodium dicyanidoaurate(I) = Na[Au(CN)₂]

Explanation: Dicyanido means 2 cyanide ions with gold(Au) in +2 oxidation state.

Cyanide ions have a negative charge of -1, so balancing the overall charge of the coordination compound to be 0, no. of sodium ion is 1.

Formula: Na[Au(CN)₂]

(b) Tetraamminechloridonitrito-N-platinum (IV) sulphate =

[Pt(NH₃)₄Cl(NO₂)] SO₄

Explanation: Anion is SO₄^2-.Tetraammine means 4 neutral ammonia molecules, nitrito-N means nitro group bonded to a central atom via the lone pair of electron of nitrogen and platinum in +4 state. Balance overall charge as 0.

Formula: [Pt(NH₃)₄Cl(NO₂)] SO₄