The molecular structure of 5 in the crystal (displacement ellipsoids at 50% probability level, hydrogen atoms omitted for clarity, i Pr groups drawn as ball-and-stick models). Selected experimental bond lengths: 3 : Li1C1: 216.6(2) pm, Li1Cp cent : 184.9(2) pm; 4a : C1Li1: 210.4(2) pm, Li1Cp cent : 170.7(5) pm; 4b : C1Li1: 210.0(8) pm, Li1Cp cent : 153.1(7) pm; 5 : Al1/2N1/2: 181.7(2)182.3(2) pm, Al1/2C Cp : 202.5(3)/202.8(3) pm, N1/2C Ad : 146.5(3)/147.3(3) pm.