Abstract: | Zintl Anions of Silicon in the Halides La3Cl2Si3 and La6Br3Si7 La3Cl2Si3 and La6Br3Si7 are prepared at temperatures of around 950 °C from LaX3 (X = Cl, Br), La metal and Si as starting materials. La3Cl2Si3 crystallizes in C2/m with a = 1802(3), b = 420.6(4), c = 1058(2) pm, β = 97.9(2)°, and La6Br3Si7 in Pmmn mit a = 1686.9(2), b = 412.93(11), c = 1185.2(1) pm. In both compounds the Si atoms are located in trigonal prisms of La atoms, which are connected through common triangular and rectangular faces to form layers. The bromine atoms connect the metal atom double layers. In La3Cl2Si3 the Si atoms form zig‐zag chains, in La6Br3Si7 chains build up from ‐connected Si12 rings. Both compounds are metallic conductors. |