  The thermodynamics of the Gibbons-Maeda-Garfinkle-Horowitz-Strominger (GMGHS)
charged black hole from string theory is reformulated within the context of the
recently developed formalism of geometrothermodynamics. The geometry of the
space of equilibrium states is curved, but we show that the thermodynamic
curvature does not diverge when the black hole solution becomes a naked
singularity. This provides a counterexample to the conventional notion that a
thermodynamical curvature divergence signals the occurrence of a phase
transition.
