Electrical Conductivities of Molten Bi–BiI3 Solutions

Abstract

The electrical conductivities of Bi-BiI. solutions were measured above the consolute temperature over the entire composition range. The specific conductance increases continuously and monotonically with increasing metal composition; e.g., at 500°C the increase is from 0.32 for pure BiI. to 7170 (0 cm)-l for the metal. The temperature coefficients of the specific conductance are positive for all compositions except those greater than 80 mole % bismuth. Both a positive and negative temperature coefficient were observed at 80%. The results are discussed in terms of various mechanisms of conductance.

Conductivities of Room Temperature Molten Salts Containing AlCl3, Measured by a Computerized Direct Current Method

“…Duke and Bissell [6 ] also demon strated the utility of the d.c. method at the higher temper atures of the KCl-LiCl system. Grantham and Yosim [7] have performed ac and dc conductivity measurements of various Bi-Bil3 melts and found agreement between them within 0.1%. Therefore, in the present study a com puterized measurement system using a d.c. four-probes method processed through a computer program has been employed.…”

Presence of Li Clusters in Molten LiCl-Li

“…This effect can therefore account for the consumption of what would be “free” electrons under metal saturated conditions, resulting in a suppression of the electrical conductivity of the melt 43 45 46 47 48 49 . Similarly, the F − center model does not apply to polyvalent metal-salt solutions such as Bi-BiI 3 50 51 . In a manner analogous to the proposed formation of Li clusters, metal salt solutions containing transition metals form abnormally reduced complexes referred to as subhalides.…”

“…Furthermore, the alteration to the Li|Li + open circuit potential that occurs with varying concentrations of Li in the melt is not Nernstian; it behaves as if the activity of the reduced form, Li is not unity and changes based on concentration 13 . These facts suggest that molten solutions of LiCl and Li contain additional Li complexes other than LiCl and Li; a hypothesis that has been debated without confirmation for decades 15 20 21 46 48 50 51 52 . It was noted that Li clusters possess significantly different ionization potentials than metallic Li 36 37 ; therefore they are expected to exhibit thermodynamic activity that is different from the metallic phase.…”

The origin of the conductivity maximum in molten salts. II. SnCl2 and HgBr2

“…(ii) Faradaic rectification (in alternatingcurrent mode) and electrode deposit effects (in direct-current mode or from faradaic rectification) are assumed to be absent in the Grantham and Yosim experiments, since their first experiments (involving BiI 3 ) were performed three ways (2-electrode alternating current, and 4-probe and 2-probe direct current), all producing common conductivity values to within 0.1%. 57 Any potentially insulating deposits are expected to be less stable at the elevated temperatures where conductivity begins to fall; for instance, a hypothetical Hg 2 Br 2 deposit would decompose near 345 • C, 51 before the conductivity fall. (iii) Effects due to loss of liquid to the vapour phase (e.g., coupled equilibria of the type ionic/molecular with liquid/vapour) are difficult to imagine.…”