Abstract: | Condensed Al6 Rings in the Subiodides La3Al2I2 and La2Al2I The subiodides La3Al2I2 and La2Al2I are reported. The compounds were prepared from stoichiometric mixtures of lanthanum, aluminium, and LaI3 under Ar atmosphere in sealed Ta ampoules at 920–950 °C and 980–1000 °C, respectively. La3Al2I2 crystallizes in space group C2/m with a = 19.73(2) Å, b = 4.318(1) Å, c = 12.348(9) Å and β = 121.49(3)°, La2Al2I in P63/mmc with a = 4.3718(8) Å and c = 17.605(2) Å (isotypic with Gd2Fe2I). Both structures are characterized by sheets of trigonal prisms formed by the La atoms centered by aluminium, the latter being arranged in Al6 rings. These rings are connected to chains in La3Al2I2 (dAl(2)–Al(2) = 2.550(4) Å and 2.615(2) Å, respectively) and layers (dAl–Al = 2.533(1) Å) in La2Al2I. Both compounds are metallic conductors. The electronic structure of both compounds is discussed based on band structure calculations. |