Single crystals of A(x)Fe(2-y)Se(2) (A=K or Cs) were grown by the Bridgman method. The crystals are superconducting with T-C approximate to 30 K. Using the micro-X-ray fluorescence method for K- and Cs-containing crystals compositional ranges indispensible for superconductivity were found. (C) 2012 Elsevier B.V. All rights reserved.