Three new chromium-based ammine borohydrides were synthesized by ball milling CrCl3 center dot nNH(3) (n = 3-5) and LiBH4 in a molar ratio of 1:3. Thermogravimetric analysis-mass spectrometry (TG-MS) measurements showed that the chromium-based ammine borohydrides release H-2 in the temperature range of 100-170 degrees C, concurrent with the evolution of a small amount of NH3 evolution. The dehydrogenation purity increases with decreasing coordination number of ammonia, with the highest dehydrogenation purity (91.8 mol%) achieved for CrCl3 center dot 3NH(3)/3LiBH(4). Further improvement on the dehydrogenation of CrCl3 center dot 3NH(3)/3LiBH(4) is conducted by the addition of ZnCl2. The 0.5 mol ZnCl2 assisted sample is able to release 7.4 wt.% of hydrogen with a purity of 98.8 mol%. Copyright (C) 2015, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.