Non tetragonal

Non-Tetragonal Non-tetragonal OSj complexes are rare, and to our knowledge, Os2(Ph2PCg 114)2014 with cyclometalated PPhj ligands, is the only structurally characterized example (Figure 8.27)... 

The above technique has the practical inconvenience of requiring as many different sets of Tchebyschev coefficients as the unit cell non equivalent sublattices. Furthermore, for non cubic systems, these coefficients depend on the lattice distortion ratios. Namely, for tetragonal lattices different sets of coefficients are required for each value of c/a. This situation has made difficult the implementation of KKR and KKR-CPA calculations for complex lattice structures as, for example, curates. 

Hardness also depends on which face of a non-cubic crystal is being indented. The difference may be large. For a crystal with tetragonal symmetry the face that is normal to the c-axis can be expected to be different from those that are normal to the a-axes. Similarly the basal faces of hexagonal crystals are different from the prism faces. One extreme case is graphite where the resistance to indentation on the basal plane is very different than the resistance on the prism planes. 

For higher integer spins the number of allowed zero-field interaction terms further increases, and so does the convolution of comparable effects, except once more for a unique term that directly splits the highest non-Kramer s doublet. For S > 3 we have the addition, valid in cubic (and, therefore, in tetragonal, rhombic, and triclinic) symmetry ... 

MCrFj (M = K, Rb, or NH ) have been isolated from aqueous media and shown to have tetragonal unit cells and to be paramagnetic with antiferromagnetism at very low temperatures. Sr2Cr"Cr Fj2 and related non-stoicheiometric phases with calcium and barium have been isolated and identified. ... 

Because of the inherently non-equilibrium nature of the production route, the first question which needed to be answered was whether the phases present in the alloy were in fact stable, so that equilibrium calculations could actually be used to design these alloys. To this end CALPHAD calculations were combined with a detailed experimental characterisation of a Fe7oCrigMo2B o alloy (Kim et al. 1990, Pan 1992). The TEM and XRD results confirmed earlier work (Xu et al. 1985) which stated that an orthorhombic boride M2B was present and its composition was Cr-rich. However, they also showed that a proportion of the borides ( 10%) were Mo-rich and that the Fe-based matrix was martensitic. The latter result was particularly surprising because of the high level (20at%) of a-ferrite stabilisers Cr and Mo. Furthermore, initial analysis of difiiaction patterns from the TEM work indicated that the shuctuie of the Mo-rich boride was a tetragonal type whose structure had not been reported in previous literature (Kim and Cantor 1988). 

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