Salt, crystal structure

In the case of lithium orthoniobate, Li3Nb04, no meta-stable phase was found that had a rock-salt crystal structure with disordered cation distribution [268]. Nevertheless, solid solutions Li2+xTii-4xNb3x03, where 0 < x < 0.22, have a monoclinic structure at low temperatures and undergo transformation to a disordered NaCl type structure at high temperatures [274]. 

The tannins influence calcium salt crystal structures to produce the easily dispersible calcite (cubic structure) rather than the scaleforming aragonite (rhombic structure). 

Calcium salt crystal structures producing calcite 406... 

A ternary reciprocal system is a system containing four components, but where these components are related through a reciprocal reaction. One example is the system LiCl-LiF-KCl-KF. Solid LiCl, LiF, KC1 and KF are highly ionic materials and take the rock salt crystal structure, in which the cations and anions are located on separate sub-lattices. It is therefore convenient to introduce ionic fractions (Xj) for each sub-lattice as discussed briefly in Section 3.1. The ionic fractions of the anions and cations are not independent since electron neutrality must be fulfilled ... 

Although there is no report of an X-ray structural study of a 5-R-thianth-renium salt, crystal structures have been determined for three of the... 

Ferrous oxide is known as wustite (FeO), and it has the NaCl (rock salt) crystal structure. Accurate chemical analysis demonstrates that it is non-stoichiometric it is always deficient in iron. The FeO phase diagram (Figure 5.25) illustrates that the compositional range of wustite increases with temperature and that stoichiometric FeO is not included in the range of stability. Below 570 "C, wustite disproportionates to a-iron and Fe304. 

Two very simple descriptions of the rock salt crystal structure are also given. According to one, the sodium and chloride ions occupy positions with point-group symmetry m3m forming a checkered pattern in the Fm3m space group. According to the other description, the structure consists of two cubic sublattices in parallel orientation, one of sodium ions and the other of chloride ions. 

For several of the siliconium salts crystal structure analyses were obtained, confirming the pentacoordination and the ionic nature of the compounds (well separated cations and anions). The crystal structures for 90a(OTf), 90c(OTf), 91a(OTf), 91a(AlCl4), and 93a(OTf) are depicted in Figs. 47-51, respectively. Further structural support is found in the 29Si NMR chemical shifts (Table XXVI). A remarkable observation in Table XXVI is the nearly equal 29Si chemical shifts of siliconium salts sharing the same silicon complex, but with different anions [e.g. 91a(OTf), 91a(Br), and 91a(AlCl4)] the equal shifts are the evidence that the siliconium cations are essentially independent of... 

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