Sodium zirconium silicate compounds

The values determined by [74SH1/CHU] are selected by this review but the uncertainties have been increased since the experimental data are unavailable. 

Warhus et al. [88WAR/MAI] measured the specific heat of Na2ZrSi207(s) from 100 to 800 K using adiabatic and differential scanning calorimetry. Values calculated by [88WAR/MA1] for the thermochemical properties are as given below  

The values are selected by this review the uncertainties have been estimated in this review for the heat capacity, enthalpy and Gibbs energy. The value for the enthalpy is in reasonable agreement with the value determined by [74SH1/CHU] (- 3622.9 kJ-moP ) by isothermal calorimetry the value of [88WAR/MA1] is preferred in this 

The enthalpy and entropy of Na4Zr2Si30 2(s) was also measured by [88WAR/MAI] from following the reaction 

The uncertainties have been estimated in this review. Shibanov and Chukhlantsev [74SH1/CHU] obtained an enthalpy of -6356.8 kJ-mol for this compound again, the data of [88WAR/MAI] is preferred. From the enthalpy and entropy values and the entropies of Zr(s) (Section V. 1.1.2.1), Na(s), Si(s) and 02(g) (Chapter IV), the Gibbs energy of formation of the compound is  

---

In addition to the above, preparation in w/o microemulsions of nanoparticles of various other types of compounds, viz. silica-coated iron oxide, Fe203-Ag nanocomposite, oxides of ytrium, erbium, neodymium, vanadium and cobalt, titanates of barium and lead, ferrites of barium, strontium, manganese, cobalt and zinc, oxide superconductors, aluminates, zirconium silicate, barium tungstate, phosphates of calcium, aluminium and zinc, carbonates of calcium and barium, sulphides of molybdenum and sodium, selenides of cadmium and silver etc. have been reported. Preparative sources and related elaboration can be found in [24]. 

Also, the compound can be made by fusion of Si02 and Zr02 in an arc furnace, or by reacting a zirconium salt with sodium silicate in aqueous solution. 

A rapid procedure has been described10 based on sodium peroxide bomb fusion, for the determination of silicon and halogen in fluorine-containing organosilicon compounds and resins. The silicon is separated from the decomposition product as zinc silicate and estimated gravimetrically as silica. The filtrate is concentrated, acidified and, when necessary, reduced with sulphur dioxide. Chloride, bromide or iodide is then determined by the usual methods. Fluoride can be determined in neutral solution either gravimetrically as calcium fluoride, or volumetrically with zirconium tetrachloride or thorium nitrate, or directly in the decomposition solution by titration with zirconium tetrachloride. 

---