410 
ELEMENTARY CHEMICAL MICROSCOPY 
EXPERIMENTS. 
a. Test for Fe in simple salts. 
b. Test in complex mixtures with other elements which will be precipitated 
K4Fe(CN)6. ' , 
NICKEL. 
Crystal Forms and Optical Properties of Common Salts 
of Nickel. 
A. ISOTROPIC. 
Ammonia nickel nitrate (I). 
B. ANISOTROPIC. 
Hexagonal. 
Tetragonal. 
Orthorhombic. — Sulphate. 
Monoclinic. —Acetate; chloride; nitrate; sulphate; 
ammonium-nickel sulphate; potassium- 
nickel sulphate. 
T riclinic. 
DETECTION. 
CHs - C = NOH 
A. By Means of Dimethyl Glyoxime, I 
CH3 - C = NOH 
To a drop of the solution to be tested add ammonium hydroxide 
until in slight excess. Decant the solution of the hydroxides 
which have been dissolved by the ammonium hydroxide, from 
those which are insoluble. Close to the clear ammoniacal drop 
place a large drop of a freshly prepared saturated solution of 
dimethyl glyoxime. Cause the ammoniacal drop to flow into 
the reagent. 
Nickel yields an immediate rose-pink or magenta-colored 
precipitate — at first amorphous in character, later changing into 
a felt of exceedingly fine acicular crystals. Near the edges of 
the crystalline mass tiny needles form in star-like and irregular 
bristling clusters. Often a yellow precipitate is first formed, 
changing only slowly into pink. 
The nickel salt of dimethyl glyoxime has the formula 
