Melts molar volume

In the limiting case, if one of the components possesses a very strong covalency the molar volume of the system will decrease. Melts of NaF - A1F3 are an example of such systems. 

Fig. 60. Isotherms (800°C) of molar volume (top) (after Agulyansky et al. [322]) and specific conductivity (bottom) (after Agulyansky et al. [3241) of the melts KF- K2TaF7 (I) andKCl - K2TaF7 (2).

As a whole, the KF — TaF5 system forms melts that are characterized by a decrease in molar volume and increase in molar conductivity, as demonstrated in Fig. 64. This behavior enables classification of the system as a lib-type... 

Figure 6.8 Surface tension of fused salts as a function of melting temperature normalized with the molar volume TvapVm2n [14, 15].

Lindemann6 said melting would occur when jc became some significant fraction, a, of r, say of the order of 0.1. Now Equation (3.30) can be written in terms of the molar volume, Vm, and a ... 

Table 13.1). In the solid P(CH4) > P(CD4) but the curves cross below the melting point and the vapor pressure IE for the liquids is inverse (Pd > Ph). For water and methane Tc > Tc, but for water Pc > Pc and for methane Pc < Pc- As always, the primes designate the lighter isotopomer. At LV coexistence pliq(D20) < Pliq(H20) at all temperatures (remember the p s are molar, not mass, densities). For methane pliq(CD4) < pLiq(CH4) only at high temperature. At lower temperatures Pliq(CH4) < pliq(CD4). The critical density of H20 is greater than D20, but for methane pc(CH4) < pc(CD4). Isotope effects are large in the hydrogen and helium systems and pLIQ/ < pLiQ and P > P across the liquid range. Pc < Pc and pc < pc for both pairs. Vapor pressure and molar volume IE s are discussed in the context of the statistical theory of isotope effects in condensed phases in Chapters 5 and 12, respectively. The CS treatment in this chapter offers an alternative description.

The Clausius-Clapeyron equation describes the univariant equilibrium between crystal and melt in the P-Tfield. Because molar volumes and molar entropies of molten phases are generally greater than their crystalline counterparts, the two terms and AFfusion both positive and we almost invariably observe an... 

Table 6.10 Parameters for calculation of molar volume of silicate melts at various T conditions (after Stebbins et al., 1984). Resulting volume is in cm /mole. ...

Molar Volume, Thermal Expansion, and Compressibility of Silicate Melts... 

Like heat capacity, the molar volume of chemically complex silicate melts may also be obtained through a linear combination of the molar volumes of molten oxide components—i.e.,... 

Bottinga and Weill (1970) applied equation 6.76 extensively, and it was later recalibrated by Stebbins et al. (1984). In the latter model, the molar volume of the melt and its modification with T are calculated through the equation... 

Table 9,9 Interpolation parameters giving solubility of Ar in silicate melts as a function of R Standard state of reference for gaseous phase is pure gas Ar at P = 15 kbar and T = 1600 °C. Concentration is adopted standard state for Ar in melt. is molar volume of Ar in melt,...

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