16 
The Philippine Journal of Science. 
1921 
Cl 
H 3 N | nh 3 
8 
Pt V 
H 3 N | NHa 
Cl 
THE CARBON GROUP 
i n ii 
-C-, —Si— -Ge— , (Ge ), Sn ( 
(i) ii an) 
Pb (— Pb — ). 
Vacancies in shell = 4. 
There is unmistakable evidence that there are definitely four 
vacancies in the shell of each of these atoms. Sn" and Pb" 
are predominantly electropositive; but, as the relation of these 
atoms to the “inert group” has been established by physical evi- 
dence, each containing 4 less electrons than the corresponding 
inert atom, we have good reason to believe that this fact plays 
a large part in determining their chemical properties. This idea 
is substantiated by the behavior of — Sn — and Pb — in 
organic compounds. 
The ordinary carbon-hydrogen-oxygen compounds are ex- 
pressed in the proposed system exactly in the same manner as is 
customary among organic chemists. The peculiar compound CO, 
however, has never been successfully explained except by Lang- 
muir’s hypothesis that the two kernels share 5 pairs of electrons, 
1 pair being held rather closely by the kernels and the other 4 
pairs in an octet external to both kernels. In this case the va- 
lence of each atom is increased by 2, because a stable arrange- 
ment of 10, instead of 8, shell electrons is formed- 
EXAMPLES 
+ 
Pb 4 :::: 0 0 = Pb = 0 
H Cl 
Ge — H Cl — Sn — Cl 
cl’o O = c = o 
+ 
Sn H - 
-Sn-), 
% 
H 
Cl 
