Dark-red air-stable crystals of Ir₈Se₂₈Br ₁₄·2H₂O were obtained by reacting iridium in an excess of selenium and selenium tetrabromide at 300 °C for one week. The crystal structure is monoclinic (space group P2₁/n) with a = 1274.66(3) pm, b = 1211.48(3) pm, c = 1743.82(4) pm, and β = 91.227(1)° at 296(1) K. The structure consists of uncharged clusters Ir₈Se ₂₈Br₁₄ = (Ir³⁺)₈(Se₂ ^2-)(Se₄^2-)₆(SeBr₂) ₂(Br^-)₁₀ with two water molecules attached to each of them. Selenium adopts three different oxidation states, -I in the diselenide dumbbell, -I and ±0 in the tetraselenide chains, and +II in the SeBr₂ units. The iridium(III) cations are coordinated octahedrally by selenium atoms and bromide ions. The octahedra share common vertices, while the oligoselenide anions provide high intra-cluster connectivity: μ₆-η² in the case of Se ₂^2- and μ₄-η³ for Se ₄^2-. In parts the cluster resembles a cut-out of the rhombohedral Ir₃Se₈ framework structure. The ellipsoidal clusters form an excellent approximation of the mathematically predicted densest known packing of ellipsoids, featuring the coordination number of 14.