Succinonitrile (SCN)-carbon tetrabromide (CTB) alloys for different concentrations of CTB (C-0) were unidirectionally solidified with a constant temperature gradient (G = 7.5 K/mm) at different growth rates (V = 6.5-103.5 mu m/s). The primary dendrite arm spacings, secondary dendrite arm spacings and dendrite tip radius were measured as a function of growth rates and compositions. Theoretical models for the dendrite arm spacings and tip radius have been compared with the experimental observations, and a comparison of our results with the current theoretical models and previous experimental results have also been made. (c) 2005 Elsevier B.V. All rights reserved.