Two kinds of Zn3B10O18 center dot 14H(2)O morphologies, a cabbage-like micro-/nanostructure and a nanobelt, have been prepared by solution method. All the samples were characterized by XRD, IR, EDS. TG-DTA techniques, chemical analysis and SEM. The flame retardant properties of the prepared Zn3B10O18 center dot 14H(2)O nanomaterials were investigated by the thermal analysis method and limited oxygen index method, showing that the nanobelt sample with the smaller size had the better behavior than the cabbage-like micro-/nanostructure sample. Through an appropriate thermochemical cycle, the standard molar enthalpies of formation of -(11803.1 +/- 8.0) kJ mol(-1) for cabbage-like Zn3B10O18 center dot 14H(2)O micro-/nanostructure and -(11791.2 +/- 8.0) kJ mol(-1) for Zn3B10O18 center dot 14H(2)O nanobelt have been obtained from measured different enthalpies of solution, together with the standard molar enthalpies of formation of ZnO(s), H3BO3(s), and H2O(1), which shows that their stabilities decrease gradually with the decrease of Zn3B10O18 center dot 14H(2)O sizes. (C) 2012 Elsevier B.V. All rights reserved.