Two‐ and Three‐Dimensional [IrSi] Networks in the Silicides Sm3Ir2Si2, HoIrSi,and YbIrSi

New intermetallic rare earth iridium silicides Sm₃Ir₂Si₂, HoIrSi, and YbIrSi were synthesized by reaction of the elements in sealed tantalum tubes in a high‐frequency furnace. The compounds were investigated by X‐ray diffraction both on powders and single crystals. HoIrSi and YbIrSi crystallize in a TiNiSi type structure, space group Pnma: a = 677.1(1), b = 417.37(6), c = 745.1(1) pm, wR2 = 0.0930, 340 F² values for HoIrSi, and a = 667.2(2), b = 414.16(8), c = 742.8(2) pm, wR2 = 0.0370, 262 F² values for YbIrSi with 20 parameters for each refinement. The iridium and silicon atoms build a three‐dimensional [IrSi] network in which the holmium(ytterbium) atoms are located in distorted hexagonal channels. Short Ir–Si distances (246–256 pm in YbIrSi) are indicative for strong Ir–Si bonding. Sm₃Ir₂Si₂ crystallizes in a site occupancy variant of the W₃CoB₃ type: Cmcm, a = 409.69(2), b = 1059.32(7), c = 1327.53(8) pm, wR2 = 0.0995, 383 F² values and 27 variables. The Ir1, Ir2, and Si atoms occupy the Co, B2, and B1 positions of W₃CoB₃, leading to eight‐membered Ir₄Si₄ rings within the puckered two‐dimensional [IrSi] network. The Ir–Si distances range from 245 to 251 pm. The [IrSi] networks are separated by the samarium atoms. Chemical bonding in HoIrSi, YbIrSi, and Sm₃Ir₂Si₂ is briefly discussed.