A method of forming .alpha.-alane. The method includes reacting aluminum trichloride and an alkali metal hydride to form an alane-ether complex solution. An aqueous diethyl ether solution is optionally added to the alane-ether complex solution to form a partially hydrolyzed ether/alane-ether complex solution. A solution of a first crystallization additive is added to the alane-ether complex solution or to the aqueous ether/alane-ether complex solution to form a crystallization solution. The first crystallization additive is selected from the group consisting of polystyrene, polybutadiene, polystyrene-co-polybutadiene, polyisoprene, poly-alpha-methylstyrene, polystyrene-co-polyindene, poly-alpha-pinene, and mixtures thereof. Optionally, a second crystallization additive is added to the crystallization solution. The second crystallization additive is selected from the group consisting of squalene, cyclododecatriene, norbornylene, norbornadiene, a phenyl terminated polybutadiene, 2,4-dimethyl anisole, 3,5-dimethyl anisole, 2,6-dimethyl anisole, polydimethyl siloxane, and mixtures thereof. Solvents are removed from the crystallization solution to crystallize the .alpha.-alane.