Etude des fautes d'empilement dans les kaolinites partiellement désordonnées. II. Modèles d'empilement comportant des fautes par rotation

This work describes a method of calculating the profile of the X-ray diffraction bands (for a powder) for partially disordered kaolinites containing rotational stacking faults. The profiles of the bands have been calculated for stackings containing ±2π/3 rotational faults. These faults are such that two first neighbouring layers (i) are translated as in a perfect kaolinite but additionally rotated by +2π/3 or −2π/3; (ii) are disposed strictly as in dickite, or (iii) start with the enantiomorphic kaolinite structure. Among the different models envisaged, only the model with faults of the first type mentioned above seems to agree with the experimental profiles of the different natural kaolinites.