The structure of the novel pure silica zeolite ITQ-45 has been recently determined in our laboratory. However, although it appears to be a fully connected framework, 29Si NMR analysis of the calcined and washed samples indicates the presence of well ordered Q3 species, i.e. silicon atoms not fully connected to their neighbours. Our objective will be determining the precise location of these Si-OH groups in order to understand the behaviour and properties of this material, and to relate it to the apparently fully connected framework of the zeolite obtained from XRD