Page:Outlines of Physical Chemistry - 1899.djvu/96

 ��OUTLINES OF PHYSICAL CHEMISTRY

��refractions of an acid and its corresponding aldehyde. By deducting six times the value of 0H 2 from the molecular refraction found for hexane (C 6 H U ) the constant (or rather double of it) is obtained for hydrogen : H 2 = 2*205. This same value is arrived at by deducting 1*506 for oxygen, and 9*14 for 2CH 2, from the molecular refraction of alcohol (C 2 H 6 0).

We have therefore : from which C = 2-865.

It is only necessary to examine some substances con- taining chlorine, bromine, &c., in order to find the values given in the following table of atomic refractions :

��—

�For yellow

light

(sodium)

�For red light

(hydrogen)

(BrVhl)

�c

�H

�0'

�0"

�

�CI

�Br

�I

�=

�—

��Remarks

��Hydroxyl oxygen. Intra-radioal oxygen. Simple ether oxygen.

��Doable linkage between two car- bon atoms.

Triple linkage between two carbon atoms.

The refractive power of nitrogen is very variable. Its value in the different series increases in the following order : fatty amines — primary, secondary, tertiary, primary aro- matic amines, hydrocyanic acid and nitriles, oximes, (for red hydrogen light) and 2.446 to 4.868 (for yellow

1 See Brühl's publications in the Berichte der deut. chem. Gesell, particularly Ber. 31, 1367 (1898).