Temperature Stability Ranges

Phase Temperature stability range, C Ref. Year Remarks 

Phase Temperature staoility range, °C Ref. Year Remarks 

Remarks. 1. Phosphides and sulfides are stable up to the melting point under the pressure of the corresponding vapor of phosphorus and sulfur. 2. For temperature stability ranges of sulfides Me2S3 of the rare earth metals, see [1072].  

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Element Temperature Stability range/°C Pressure/GPa Crystal structure Lattice parameters/pm Atomic volume pm3/106 Molar volume/ cm3/mol Density/ g/cm3... 

Operando methodology aims to define and characterize structure/function relationships which must be interfaced with rate and dynamics measurements of the elementary steps. Recent years have shown a marked increase in the presence of spectroscopic investigations of catalytic reactions in literature (see Catalysis Today, 113 issues 1-2). For example, operando techniques were used to determine the temperature stability range of two NOx reduction catalyst types, (NH4)[Co(H20)2]Ga(P04)3 vi. (NH4)[Mn(H20)2]Ga(P04)3. Fig. 5 shows that the catalyst with manganese changes in structural stability around 673 K. Inspection of the catalyst with cobalt shows that there is no structure modification at a temperature below 673 K. 

A great variety of formulas for this phase can be found, e.g. 48 s°). Some of these data are dubious, others are only correct in respect of the temperature-dependent solid solution range of the Y-phase. However, the Y-phase should be described as a compound with a Fe Mo ratio of 1 4, as this represents the only formula valid for the temperature stability range from slightly below 800 °C up to its melting point. The Y-phase can only be synthesized above 535 15 °C46 it is quench-able and probably remains metastable at room temperature. 

However, the composition and temperature stability range of this ternary zinc-molybdenum sulfide, which is stable at elevated temperature within the Mo—Mo2>06S3-ZnS triangle of the ternary Zn-Mo—S system, is still obscure. This phase can also coexist with tungsten. Completely unknown are the stability relations of the strongly anisotropic compound which partly formed in experiment No. 3. 

The mineral phases observed in this study are summarized in Table II. For each phase, the mixtures that yielded them and their observed temperature stability ranges are given. When these phases are encountered in X-ray diffraction studies of ceramic pastes, it should be possible to determine the maximum temperature at which the ceramic was heated, providing it did not exceed 1100 °C and contained a mixture close to the clay-carbonate... 

New weighing compositions in gravimetric analysis and the determination of their temperature stability ranges. 

Fig. 4.53 Approximate stability range of known calcium silicate hydrates under hydrothermal conditions. The vertical lines indicate C/S mole ratios, their length is proportional to the temperature stability range the width of their names gives an approximate range of deviation from then-theoretical composition. The horizontal lines mean also the change of composition. At temperature 374 °C the critical point for water is indicated, at higher temperatures the saturated water vapor pressure is about 40 MPa. Above the ab line, the anhydrous compounds occur, in the phases marked between the straight lines ab and cd, water is present as OH" ions however, in xonotlite and truscotite there is presumably the molecular water below the cd line there are the Si-OH groups containing phases, as well as the water molecules, OH" ions and the two types of HjO. (after [156])...

Refractories are classified on the basis of (i) physical form, (ii) refractoriness (temperature stability range), (iii) chemical composition and (iv) method of manufacture. 

And indeed, the temperature stability range as well as the electrochemical stability (both against oxidation and reduction) is very pronounced for many of the commonly used Ionic Liquids. The same is true for their high non-inflammability [1,4, 5, 7]. 

Chapter I concludes with data on the temperature stability ranges of refractory compounds, obtained principally from the phase diagrams of the corresponding binary systems. 

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