Antimony
Definition and meaning of Antimony in chemistry.
Antimony is a lustrous, silvery-gray metalloid featuring the chemical symbol Sb and an atomic number of 51. It is a hard, exceptionally brittle crystalline solid that distinctively exhibits physical and chemical properties intermediate between those of true metals and nonmetals. Its chemical symbol Sb originates from stibium, the ancient Latin name for antimony sulfide, which was used historically as a cosmetic eye cosmetic.
In more detail
Found in group 15 of the periodic table, affectionately known as the pnictogens, antimony is formally classified as a metalloid and characterized by noticeably poor thermal and electrical conductivity compared to standard metals. It occurs in nature predominantly as the prevalent sulfide mineral stibnite (Sb2S3), though it can occasionally be discovered in its native elemental metallic form within specific geological deposits. Antimony typically exhibits formal oxidation states of +3 and +5, easily forming various complex oxides, distinct halides, and diverse organometallic compounds. When actively heated in ambient air, the metalloid burns brilliantly and vigorously to yield dense white fumes of antimony trioxide (Sb2O3). A notable, highly unusual physical anomaly of antimony is that, similar to liquid water, it expands slightly upon transitioning from a liquid to a solid state. This remarkably rare volume-expansion property makes antimony highly valuable in industrial manufacturing for casting sharp, highly detailed metal alloys like type metal.
Key facts
| Field | General Chemistry |
|---|---|
| Symbol | Sb |
| Atomic number | 51 |
| Atomic mass | 121.76 u |
| Category | Metalloid |
| State at room temperature | Solid |
| Melting point | 630.63 °C |
| Boiling point | 1635 °C |
| Common mineral | Stibnite |
Antimony is commonly alloyed with lead to significantly increase its hardness and mechanical strength, creating durable grid materials essential for modern lead-acid storage batteries.
Frequently asked questions
Is antimony considered a true metal?
Antimony is classified as a metalloid, meaning it possesses a unique mixture of both metallic and nonmetallic physical and chemical characteristics.
Why is antimony frequently added to metal alloys?
It increases the overall hardness and strength of soft metals like lead and prevents shrinkage during casting because it expands upon freezing.