19, 1 Perkins: The Octet Theory of Valence 17 
18 " 
a 
H—C—C—O-H ==> 
| fi 
H H 
THE NITROGEN GROUP 
| | bm 
| 
Boy if pp eeiaeg eitow ah ig ye cay 
i 
Vacancies in shell =3. 
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 
(=) = (22) 
N =N, N = O, and — C = N and are explained by Langmuir as 
being “‘isosteric” with C=0. 
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—O—H, described in connection with hydrogen. The ammo- 
nium ion, however, is much more stable than OH, 
Poe) yay 
| 
4 
He NN + ce. Cl .- 
| 
H 
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 —O—, as: 
| 
O 5 pees 6, 
NxoN=O 8 | I 
O=N-—-N=0 Ow~mN-NxO 
O O H—O-N<O 
{| \| | 
O>~N—-O-NcO O 
