Alanes of the formula H
x
AlX
3–x
(x = 0, 1, 2, 3; X = Cl, Br, I) and the mixed halogen species HAlClBr were synthesized as
N
-methyl-piperidin (nmp) adducts H
x
AlX
3–x
·znmp (z = 1, 2) and HAlClBr·2nmp by different routes. The crystal and molecular structures of (H
3
Al·nmp)
2
, H
2
AlBr·2nmp, H
2
AlI·2nmp, the isotypic and isomorphous HAlBr
2
·2nmp, HAlI
2
·2nmp, as well as ACl
3
·nmp, ABr
3
·nmp, AI
3
·nmp, and HAlClBr·2nmp are described. The aluminum atoms in these molecular structures either form a pentagonal bipyramid as coordination sphere with the amine bases in apical positions or are in the center of a distorted tetrahedron (AlCl
3
·nmp, ABr
3
·nmp, AI
3
·nmp). In the nmp adduct of alane, a central Al
2
H
2
ring is formed by dimerisation of AlH
3
, each aluminum atom displaying a further nmp ligand together with two terminal hydrogen atoms. The influence of the halogen atoms on the hydrogen bonds in the iso-structural compounds were studied by IR spectroscopy, showing in both series H
2
Al
X
·2nmp and HAl
X
2
·2nmp (
X
= Cl, Br, I) a dependence of ν(Al–H) on the substitution pattern: 1770.2–1775.2–(not measured) cm
–1
(H
2
Al
X
) and 1785.0–1788.0–1791.0 cm
–1
(HAl
X
2
). The δ values of the
27
Al-NMR spectra in solution show dependences on the halide numbers bonded to aluminum and display a regular growth with heavier element in the H
2
Al
X
·2nmp series δ (
27
Al): 121.2 (Cl), 126.0 (Br), 131.5 (I)], whereas they have an unsteady evolution in the HAl
X
2
·2nmp series [δ (
27
Al): 118.0 (Cl), 122.0 (Br), 108.0 (I)] and the Al
X
3
·nmp series [δ (
27
Al): 102.1 (Cl), 104.8 (Br), 61.9 (I)].