Three transition times were observed during the chronopotentiometric study of CoCl2 in fused alkali chloride solutions. The first and third times were diffusion-controlled and did not coexist. The third was most obvious in equimolecular NaCl-KCl mixtures at 700C. It was believed to be due to the discharge of CoCl42-. The second transition time was related to a process which was not completely diffusion-controlled, and which probably involved the discharge of CoCl3-. The diffusion coefficients which were calculated from the chronopotentiometric data were smaller than those predicted from theoretical formulae by using the radius of Co2+. This behavior was attributed to the fact that Co2+ was not the ion which was being diffused (table 99).

Y.K.Delimarskii, V.F.Grishchenko, N.I.Parkhomenko: Ukrainski Khimicheski Zhurnal, 1975, 41[11], 1123-7

 

 

Table 99

Diffusivity of Co2+ Ions in Equimolecular KCl-NaCl Melts

 

CoCl2 (/cm3)

Temperature (C)

D (cm2/s)

0.493 x 105

700

1.95 x 10-5

0.494 x 105

700

2.33 x 10-5

0.986 x 105

700

2.31 x 10-5

1.484 x 105

700

1.86 x 10-5

2.473 x 105

700

1.77 x 10-5

0.990 x 105

806

2.36 x 10-5

0.059 x 105

806

3.05 x 10-5

1.486 x 105

806

2.34 x 10-5

1.981 x 105

806

2.97 x 10-5

1.996 x 105

806

2.24 x 10-5