The quindecanuclear nickel/sulfur cluster [Ni-15(mu(3)-S)(6)(mu(4)-S)(9)(PEt3)(6)](+) has been isolated by reaction of Ni(ClO4)(2). 6H(2)O with H2S and PEt3 in ethanol/dichloromethane solution and has been characterized by X-ray diffraction studies. (C) 1999 Elsevier Science S.A. All rights reserved.