Measurements of the thermal and electrical conductivities of very pure lithium, sodium, potassium, rubidium and caesium have been made down to temperatures as low as 2°K. The respective resistivities,
W
and
ρ
, may be written as the sum of an impurity resistance (
W
0
,
ρ
0
) and a so-called ‘ideal’ component (
W
i
,
ρ
i
) due to scattering by the thermal vibrations of the lattice. The terms in the thermal resistivity may be represented by
W
0
=
A
/
T
and
W
1
=
B
T
n
f
o
r
T
≤
θ
/
10
, where
n
≃ 2 and
A
= (
ρ
0
/2⋅45) x 10
8
cm deg.
2
W
-1
. Current theory predicts thatt he quantity
C
≡
Bθ
2
/
W
∞
N
⅔
should be constant, where
N
is the number of free electrons per atom and
W
is the measured high-temperature resistivity. Taking
N
= 1, the present experiments yield
C
≃ 18 ± 4. The electrical resistance may be written
ρ
=
ρ
0
+
β
T
m
f
o
r
T
<
θ
/
10
with
m
≃ 5 except for sodium, where, below 8°K ,
m
is found to increase to 6. The theoretical relationships which exist between the low-temperature ‘ideal’ resistivities and those at higher temperatures are discussed in conjunction with the measured values. It is concluded that with the existing theories, no common adjustment of
θ
can give satisfactory agreement of theory with experiment. A new simple semi-empirical expression is put forward for
W
i
which provides rather good agreement with experiment.
Alkali Metal Re-Distribution after Oxidation of 4H-SiC