Aluminum tridecamer (Al-13) salt of 70% purity can be yielded by slowly adding base to a mixed aluminum chloride solution with sodium chloride as the primary byproduct. The purity of the so-produced Al-13 solution is typically increased to >90% using sulfate precipitation and nitrate metathesis reactions (the SO42-/Ba2+ separation method). However, the presence of excess sulfate and, as demonstrated in this study, excess chloride ions can destabilize Al-13 clusters. This study applied the organic solvent precipitation technique to purify crude Al-13 salt. The solution and solid-state Al-27 nuclear magnetic resonance (NMR) spectra indicate that Al-13 purity was >95%. The infrared adsorption spectra had clear Al-13 characteristic bands. The electrospray ionization mass spectrometry (ESI-MS) tests identified Al-13(7+) species. The organic solvent precipitation method purified Al-13 clusters with minimal free Cl- ions. (C) 2010 Elsevier B.V. All rights reserved.