Gewellt und eben – La6(C2)‐Oktaederschichten in Lanthancarbidchloriden

Abstract

AbstractSheets of La6(C2) Octahedra in Lanthanum Carbide Chlorides – undulated and planeThe reaction of Ln, LnCl3 (Ln = La, Ce) and C yields the hitherto unknown compounds La8(C2)4Cl5, Ce8(C2)4Cl5, La14(C2)7Cl9, La20(C2)10Cl13, La22(C2)11Cl14, La36(C2)18Cl23 and La2(C2)Cl. The gold‐ resp. bronze‐coloured metallic compounds are sensitive to moisture. The reaction temperatures are 1030 °C, 1000 °C, 970 °C, 1020 °C, 1020 °C, 1080 °C and 1030 °C in the order of compounds given, which mostly crystallize in the monoclinic space group P21/c with a = 7.756(1) Å, b = 16.951(1) Å, c = 6.878(1) Å, β = 104.20(1)° (La8(C2)4Cl5), a = 7.669(2) Å, b = 16.784(3) Å, c = 6.798(1) Å, β = 104.05(1)° (Ce8(C2)4Cl5), a = 7.669(2) Å, b = 16.784(3) Å, c = 6.789(1) Å, β = 104.05(3)° (La20(C2)10Cl13), a = 7.770(2) Å, b = 47.038(9) Å, c = 6.901(1) Å, β = 104.28(3)° (La22(C2)11Cl14) and a = 7.764(2) Å, b = 77.055(15) Å, c = 6.897(1) Å, β = 104.26(3)° (La36(C2)18Cl23), respectively. La14(C2)7Cl9‐(II) crystallizes in Pc with a = 7.775(2) Å, b = 29.963(6) Å, c = 6.895(1) Å, β = 104.21(3)° and La2(C2)Cl in C2/c with a = 14.770(2) Å, b = 4.187(1) Å, c = 6.802(1) Å, β = 101.50(3)°. The crystal structures are composed of distorted C2 centered La‐octahedra which are condensed into chains via common edges. Three and four such chains join into ribbons, and these are connected into undulated layers with Cl atoms between them. The variations of the structure principle are analyzed systematically.