The IUPAC name of the coordination compound $[\mathrm{Co(NH_3)_6}]\mathrm{Cl_3}$ is:

**IUPAC naming of cation-anion coordination compounds.** 1. Inside the bracket (cation): name ligands alphabetically, then the metal with its oxidation state. 2. The neutral NH₃ ligand → **ammine** (not 'amine' — the spelling matters for naming). 3. Six ammine groups → **hexaammine**. 4. Charge balance: 3 Cl⁻ outside ⇒ cation charge $+3$ ⇒ Co is in oxidation state $+3$, written as **(III)**. Full name: **Hexaamminecobalt(III) chloride**.