antimony - Sciencemadness.org

10 THE METALLURGY OX ANTIMONY.
SECTION 2.—THE ELEMENT ANTIMONY.
Antimony, like phosphorus and arsenic, has several allotropic
modifications. Besides the gray form of antimony, the most
common and the best known, there is another form which is an
explosive. This latter is very unstable and changes easily to the
stable metallic form. The most unstable modification is yellow
antimony, which does not possess any metallic property, corresponding
thus to white phosphorus and yellow arsenic.
Metallic Antimony.—Pure antimony is a silver-white,* shining,
brittle metal. By slow cooling it crystallises in the hexagonal system,
isomorphic with the gray form of arsenic, while rapid cooling makes it
granular and crystalline. Moreover, when molten antimony is allowed
to solidify slowly without any disturbance, and when it is covered by a
layer of slag, a fern-like appearance is seen on the solidified surface.
This is the so-called " antimony star " or regulus antwionii stellatus.
The specific gravity is 6*5178, according to Kahlbaum, Siedler, and Eot.
The coefficient of cubical expansion, between 0° and 100°, is
0*003161. The coefficient of linear expansion depends upon the
direction taken, being 0*00001692 at 40° along the axis of the hcmidodecahedron,
and 0*00000882 at the same temperature along a
direction perpendicular to it (La,7idolt, Bernstein, Meyerhoffer).
The metal is a conductor of heat and electricity. The electrical
conductivity, in reciprocal ohms, is 2*71 104 at 0°, 2*47 104 between 0°
and 37°, 0*62 104 during melting, 0*88 104 when it changes ontirely
into a liquid state, and O'SS 10 ' 1 at 860°. The absolute conductivity
for heat is 0*042 between 0° and 30°, 0*0442 at 0°, and 0*0396 at
100° (Landolt, Burnstein, Meyerhoffer).
The specific heat is as follows :—
Temperature
Interval.
-186°to - 79
- 79 to + 18
- 7f> to - 20
- 20 to 0
0 to 4- 33
0 to H-'lOO
17 to 92
15
100
2f»0
300
Specific Heat
0-0462
0*0484
0*0499
0*0486
0-0495
0*0495
0*05079
0*04890
0*05031
0*05198
0*05366
Observer.
Bolm.
Pobal and Jalm.
Hun sen.
Gawlo.
Naccuri.
* With a slight tinge of blue, -which may be iiitonyifuul by the prespneo of
impurities in the metal.