Type VIII clathrate Ba5Ga16Sn30 (BGS) is a promising thermoelectric material with tunable carrier types. We have studied the Bridgman growth conditions by combining differential thermal analysis (DTA) and powder X-ray diffraction analysis. It is found that the raw elements Ba, Ga, and Sn react at 465 degrees C to form the type-VIII BGS compound. The DTA indicates the presence of a liquidus line above the peritectic point of BGS at 495 degrees C. By using the vertical Bridgman method, single crystals of ri-type and p-type BGS have been grown from Sn-rich and Ga-rich initial compositions, respectively. The obtained crystals of ri-type Ba8Ga16Sn30 and p-type Ba8Ga16Sn30_ Ge, (x 0.7) are 10 mm sized. On several parts cut from the grown crystals, the Seebeck coefficient and electrical resistivity have been measured up to 330 degrees C. The values weakly change along the vertical direction of the crystals, keeping the thermoelectric power factors as high as 12 and 9 mu W/K-2 cm. respectively, for n- and p-type crystals. (C) 2014 Elsevier By. All rights reserved.