Appearance and Characteristics
Harmful effects:
Like arsenic, which sits directly above it in the periodic table, the toxicity of antimony and its compounds varies according to the chemical state of the element. Many of the salts are carcinogenic.
The metallic form is considered to be less active whereas stibine (SbH3) and stibnite (Sb2S3) are extremely toxic. Antimony is toxic and immediately dangerous to life or health at 50 mg m-3 or above.
Exposure to 9 milligrams per cubic meter of air (mg/m3) of antimony as stibnite for a long time can irritate your eyes, skin, and lungs. Breathing 2 mg/m3 of antimony for a long time can cause problems with the lungs (pneumoconiosis) heart problems (altered electrocardiograms), stomach pain, diarrhea, vomiting and stomach ulcers. People who drank over 19 ppm of antimony in one sitting vomited.
Characteristics:
Antimony is metalloid, so it has some metallic properties but not enough to be classified as a true metal. Physically, it behaves like sulfur while chemically it is more metallic. Antimony’s electrical and thermal conductivity are lower than most metals’ conductivities. Antimony is a brittle, fusible, crystalline solid. It is easily powdered. Antimony also has the unusual property that (like water) it expands as it freezes. Four other elements expand when they freeze; silicon, bismuth, gallium and germanium. In addition to the usual form of antimony, there are three allotropes: yellow crystalline, amorphous black, and explosive.
Uses of Antimony
The major use of antimony is in lead alloys – mainly for use in batteries – adding hardness and smoothness of finish. The higher the proportion of antimony in the alloy, the harder and more brittle it will be. Alloys made with antimony expand on cooling, retaining the finer details of molds. Antimony alloys are therefore used in making typefaces for clear, sharp printing.
Babbit metals, used for machinery bearings, are alloys of lead, tin, copper and antimony. These metals are hard but slippery and so ideal for use as bearings. Antimony is used in the semiconductor industry as an n-type dopant for silicon. Antimony trioxide is used as a flame retardant in adhesives, plastics, rubber and textiles.