CHAPTER XIV. 
CHARACTERISTIC MICROCHEMICAL REACTIONS OF THE 
COMMON ELEMENTS WHEN IN SIMPLE MIXTURES. 
The methods of applying reagents and of performing the neces¬ 
sary manipulations arising in qualitative analysis have already 
been discussed at length in Chapter XIII, as well as the applica¬ 
tion of the simple polarizing microscope to the differentiation 
of chemical compounds in Chapter VIII. 
In the directions which follow it is assumed that the student 
is thoroughly familiar with these topics. As an aid to the 
recognition of common salts which may be met with, there has 
been given under each element the crystal system to which its 
common salts are to be referred. This has been done in the 
hope that the student will learn to employ the polarizing micro¬ 
scope and come to appreciate its many advantages as an invalu¬ 
able aid and great saver of time and labor. In these tabulations 
the following abbreviations have been used: (I) Isometric; 
(H) Hexagonal; (T) Tetragonal; ( 0 ) Orthorhombic; (M) 
Monoclinic; (Tr) Triclinic; and the salts arranged in the order 
named. 
SODIUM. 
Crystal Forms and Optical Properties of Common Salts 
of Sodium} 
A. ISOTROPIC. 
Isometric. — Chlorate.^ 
The alums (double sulphates of Na and Al, Fe, Cr) 
(I); chloride (I); bromide (I); iodide (I);^ 
molybdate (I or O). 
* In the following tabulations the data given have largely been obtained from 
Groth’s Chemical Crystallography. 
2 NaClOa although belonging to the isometric system exhibits circ ula r polari¬ 
zation in crystals. Its solution is inactive, 
* Nal forms hydrates optically active. 
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