Synthesis and crystal structures of hydrogen and carbon stabilized lutetium monochloride, LuClHx and Lu₂Cl₂C

Single crystals of the, basically, four‐layer slab structure …︁ClLuLuCl…︁ of the apparently as such nonexisting lutetium monochloride, LuCl, stabilized by interstitial hydrogen or carbon have been obtained from reactions of LuCl 3 and cesium (LuClH x , due to ubiquitous hydrogen) and C s Cl, lutetium and carbon (Lu 2 Cl 2 C), respectively, in sealed tantalum containers at elevated temperatures (above 700°C). Both exhibit so‐called 3R structures (space group R 3 m): LuClH x (a = 363.83(3), c = 2710.2(3) pm, Z = 6) crystalizes with the ZrCl type structure with hydrogen in tetrahedral interstices and Lu 2 Cl 2 C (a = 360.17(3), c = 2716.0(3) pm, Z = 3) with the tetradymite type (Bi 2 Te 2 S) with carbon in octahedral interstices between the double metal layers. Power X‐ray diffraction shows that for Lu 2 Cl 2 C a 1T structure is also adopted (a = 359.72(3), c = 909.25(9) pm, p 3 m1, Z = 1).