19 , 1 
Perkins: The Octet Theory of Valence 
17 
I' \ 
C — ■ 0 — H 0 
/ 
H 
THE NITROGEN GROUP 
I I I III (II) HI 
- N -, - P - As -, — Sb - (Sb ), Bi 
I 
( - Bi - ). 
Vacancies in shell =3. 
H 
I 
H C 
! 
H 
The system of structural formulas used by organic chemists 
has never been applied successfully to compounds containing 
“pentavalent” nitrogen. According to the proposed system ni- 
trogen never shows in these compounds a valence above 3, al- 
though, as pointed out by Langmuir, the covalence is 4. The 
three cases where nitrogen has a peculiar valence of 5 are 
<=) (=) <=> 
N N, N = 0, and — C N and are explained by Langmuir as 
(=) 
being “isosteric” with CcoO. 
The cases where nitrogen has been supposed to show a high 
valence are explained either by the borrowing union or by the 
formation of a positive ion. The formation of ammonium salts 
is strictly analogous to the reaction between H — Cl and 
H — 0 — H, described in connection with hydrogen. The ammo- 
nium ion, however, is much more stable than 0H 3 
H 
I + 
H - N - H 
I 
H 
Cl • 
In the case of nitrogen oxides and oxy-acids N has such a 
tendency to a covalence of 4, that it lends electrons, especially 
to — 0 — , as : 
N co N = 0 
0 
II 
O^N 
0 
8 
0 = N - N 
0 
0 — N cc 0 
0 0 
II II 
= 0 0 20 N — N cc 0 
H - 0 - N cc 0 
II 
180365 2 
0 
