364 PROPERTIES OF ELECTRICALLY CONDUCTING SYSTEMS 



specific conductance \i x 10 6 of mixtures of sodium chloride and potas- 

 sium chloride at 570. 17 



TABLE CXLVI. 

 CONDUCTANCE OF MIXTURES OF SODIUM AND POTASSIUM CHLORIDE AT 570. 



%NaCl 10 20 30 40 50 60 70 80 90 100 



pXlO 6 0.87 8.0 16.5 22.0 24.0 24.0 30.0 34.5 40.0 28.0 4.5 



The conductance value of 0.87 for pure potassium chloride at 570 

 has been calculated from the conductance values at somewhat higher 

 temperatures by means of Equation 132. It will be observed that the 

 conductance curve exhibits a maximum in the neighborhood of 80 per 

 cent of sodium chloride, at which point the conductance of the mixture 

 is nearly ten times that of pure sodium chloride and forty times that of 

 pure potassium chloride. Apparently, the maximum lies toward the 

 side of that component which possesses the higher conductance. Other 

 systems of mixed crystals have yielded similar results. Apparently, 

 therefore, it is a general rule that the- conductance of mixed crystals is 

 much greater than that of the pure components. 



In the case of mixtures of silver iodide with silver bromide and with 

 silver chloride, the conductance-temperature curve of the resulting mix- 

 ture exhibits discontinuities as a result of the peculiar nature of silver 

 iodide. 18 Up to 80 per cent of silver bromide, a homogeneous phase re- 

 sults initially, whose conductance curve corresponds with that of silver 

 iodide above the transition temperature of 146.5. Apparently, then, in 

 these mixed crystals, the silver bromide is present in a condition similar 

 to that of silver iodide above its transition point. The details of the 

 conductance curves of these mixtures need not be discussed further here. 

 It may be noted, however, that a study of the conductance of various 

 solid systems is capable of throwing light on the phase relations in these 

 systems. 



It will be evident from the foregoing discussion that solid electrolytes 

 exhibit a marked variety of phenomena which have an important bearing 

 on our conceptions of the nature of the conduction process, as well as 

 upon that of the structure of solid salts. The available data are as yet 

 extremely meager, but it may be expected that, as this field is further 

 developed, results of great value will be obtained. 



5. Lithium Hydride. The conductance of lithium hydride, both in 

 the solid and in the liquid condition, has been investigated by Moers. 19 



17 Benrath and Wainoff, Ztschr. f. phys t Chem. 11, 257 (1911). 



u Tubandt and Lorenz, loc. cit. 



19 Moers, Ztschr. f. anorg. Chem. 113, 179 (1920). 



