Parallel intergrowth

Nb02.5 and this was described in detail in elegant papers by Anderson (1970, 1973). Ordered phases are based on shear structures, with parallel CS planes (double crystallographic shear) separating the blocks of the ReOs lattice. Ternary and intergrowth block structures have been discovered by extensive HRTEM... 

Twinning in crystals results front the intergrowth of two or more individuals in such a way as to y ield parallelism in the ease of certain parts of the different individuals und. at the same time, other parts of the different individuals are in reverse positions in respect to each other. For example, an octahedral crystal of magnetite is twinned when one-half of the crystal is rotated ISO parallel to an octahedral facial plane. This type of twinning is known as spinel rn inirini . owing to its common occurrence in the spinel group of minerals. 

We can finally conclude that the number of chemical systems which appear to reject point-defect populations as a mode of accommodating their non-stoicheiometric behaviour is large and varied and here we have touched upon only a few which make use of planar faults or parallel lamellar or foliar intergrowth structures. The results presented show that physical terms, such as elastic strain, are of importance in controlling the microstructures of such phases, but whether they form or whether they coexist with some form of point-defect clusters may well depend in a sensitive way to the anion-cation bonding within the individual co-ordination polyhedra which made up the structure. The continuing research in this area is certain to produce new and unexpected results before complete answers to the problems posed here are found. 

The distribution of Xe atoms in the channels parallel to c and b axes of Na - and K -ferrierite and the approximate location of the cations as well as the intergrowth of ferrierite-mordenite stractures have been studied by Xe NMR of adsorbed xenon [8912]. 

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