Antimony

Dive into the intriguing world of Antimony with our comprehensive guide, crafted especially for educators. Antimony, a lesser-known yet significant element, holds a unique place in both science and history. As a teacher, understanding its complexities and conveying them to students can be challenging. Our guide simplifies this task, offering clear explanations, practical examples, and engaging teaching tips. Enhance your lessons and captivate your students with our in-depth exploration of Antimony.

What is Antimony?

Antimony is a chemical element with the symbol Sb (from Latin: stibium) and atomic number 51. A lustrous gray metalloid, it is found in nature mainly as the sulfide mineral stibnite (Sb2S3). Antimony compounds have been known since ancient times and were used for cosmetics; metallic antimony was also known, but it was erroneously identified as lead upon its discovery. The largest applications for metallic antimony are as alloying material for lead and tin and for lead antimony plates in lead-acid batteries. Alloying lead and tin with antimony improves the properties of the alloys which are used in solders, bullets, and plain bearings.

Antimony Element Information

Other Metalloids

Boron (B)

Silicon (Si)

Germanium (Ge)

Arsenic (As)

Tellurium (Te)

Antimony Formula

• Formula: Sb
• Composition: Consists of a single antimony atom.
• Bond Type: Antimony typically forms covalent bonds, leveraging its five valence electrons for bonding.
• Molecular Structure: Appears as a lustrous gray metalloid in its solid state.
• Electron Configuration: Possesses 51 electrons, with the configuration [Kr] 4d¹⁰ 5s² 5p³.
• Significance: Widely used in flame retardants, lead-acid batteries, alloys, and in the manufacture of certain microelectronics.
• Role in Chemistry: Antimony plays a crucial role in the development of materials science, particularly in alloys and flame retardant compounds.

Atomic Structure of Antimony

Properties of Antimony

Physical Properties of Antimony

Property	Description
Appearance	Silvery, lustrous gray metalloid, exhibiting a metallic shine.
Density	Approximately 6.697 g/cm³, indicating a relatively high density.
Melting Point	Melts at about 630.63 °C, showing moderate thermal stability.
Boiling Point	Boils at 1587 °C, indicative of its high thermal endurance.
Crystal Structure	Exhibits a rhombohedral crystal structure, contributing to its brittleness.
Hardness	Fairly hard, though brittle, making it difficult to machine or work with.
Conductivity	Poor conductor of heat and electricity, useful in certain alloys and compounds.
State at Room Temperature	Solid under standard conditions, maintaining its structure without degradation.

Chemical Properties of Antimony

Antimony, with the chemical symbol Sb, exhibits several interesting chemical properties:

• Reactivity with Oxygen: Antimony reacts with oxygen to form antimony trioxide (Sb₂O₃): 4Sb+3O₂→2Sb₂​O₃​ This reaction is fundamental in the production of flame retardant materials.
• Formation of Stibine: It reacts with hydrogen, forming stibine (SbH₃): Sb+3H₂→2SbH₃​ Stibine is a highly toxic gas, similar to arsine.
• Reaction with Halogens: Antimony reacts with halogens like chlorine to form antimony trichloride (SbCl₃) and antimony pentachloride (SbCl₅): $Sb+3Cl₂\to 2SbCl₃$ Sb+5Cl₂→2SbCl₃​ These are important in the synthesis of organometallic compounds.
• Formation of Antimonides: With metals, antimony forms antimonides, which are important in semiconductor technology.
• Stability in Air: Antimony is relatively stable in air, not reacting significantly at room temperature.
• Combination with Sulfur: It forms various sulfides like antimony trisulfide (Sb₂S₃), used in pyrotechnics and matches.
• Reaction with Alkalis: Antimony reacts with alkali metals to form antimonates, used in glasses and ceramics.

Thermodynamic Properties of Antimony

Property	Description / Value
Melting Point	630.63°C (1167.13°F)
Boiling Point	1587°C (2889°F)
Thermal Conductivity	24.4 W/(m·K)
Specific Heat	0.207 J/(g·K) at 25°C
Heat of Vaporization	195.2 kJ/mol
Heat of Fusion	19.79 kJ/mol

Material Properties of Antimony

Property	Description / Value
Phase at STP	Solid
Density	6.697 g/cm³ at 20°C
Young’s Modulus	55 GPa
Tensile Strength	170 MPa
Mohs Hardness	3
Elastic Modulus	55 GPa

Electromagnetic Properties of Antimony

Property	Description / Value
Magnetic Susceptibility	Diamagnetic
Electrical Conductivity	2.5×10^4 S/m at 20°C

Nuclear Properties of Antimony

Property	Description / Value
Atomic Number	51
Atomic Mass	121.760 u
Neutron Cross Section	5.6 barns (for ^121Sb)
Isotopes	^121Sb (57.21%), ^123Sb (42.79%)
Radioactivity	Natural antimony is stable. ^125Sb and ^124Sb are notable radioactive isotopes with half-lives of 2.75856 years and 60.20 days, respectively

Chemical Compounds of Antimony

Antimony forms several important compounds, each with unique properties and applications. Here are the top six antimony compounds along with their relevant chemical equations:

1. Antimony Trichloride (SbCl₃): 2 Sb+3 Cl₂​→2 SbCl₃.
   Used in flame retardants and as a chemical reagent.
2. Antimony Trioxide (Sb₂O₃): 4 Sb+3 O₂→2 Sb₂O₃​.
   Commonly used in flame retardant formulations.
3. Antimony Pentoxide (Sb₂O₅): Sb₂​O₃​+O₂​→Sb₂O₅.
   Utilized as a flame retardant and in some glass and ceramic products.
4. Antimony Sulfide (Sb₂S₃): 2 Sb+3 S→Sb₂​S₃​.
   Used in pyrotechnics, match heads, and as a pigment.
5. Sodium Antimonate (NaSbO₃): Formed by reacting antimony trioxide with sodium hydroxide.
   Used in glass decolorization and as a catalyst.
6. Antimony Pentafluoride (SbF₅): 2 Sb+5 F₂→2 SbF₅​.
   Employed in some chemical synthesis processes as a strong fluorinating agent.

Isotopes of Antimony

Isotope	Key Characteristics
¹²¹Sb	Stable isotope with natural abundance of about 57.21%.
¹²³Sb	Stable isotope, comprising about 42.79% of natural antimony.
¹²²Sb	Radioactive isotope with a half-life of 2.7238 days. Used in medical research.
¹²⁴Sb	Radioactive isotope with a half-life of 60.20 days. Used in industrial radiography.
¹²⁵Sb	Radioactive isotope with applications in nuclear medicine.
¹²⁶Sb	Radioactive isotope with a relatively short half-life, used in scientific studies.

The properties and stability of these isotopes make antimony a versatile element in various scientific and industrial applications.

Uses of Antimony

Antimony, a metalloid with the symbol Sb, has several significant uses in various industries due to its unique physical and chemical properties.

1. Flame Retardants

One of the primary uses of antimony is as a flame retardant in household goods and consumer electronics. When combined with halogenated compounds, antimony trioxide acts as an effective synergist that enhances the flame-retardant properties of these compounds. It’s used in plastics, textiles, rubber, and paints to prevent the spread of fire.

2. Alloys

Antimony is widely used in alloying to increase hardness and mechanical strength. Its most notable application is in lead-acid batteries. The addition of antimony to lead improves the battery’s charge retention and decreases the amount of maintenance required. Antimony alloys are also used in bearings, solder, and pewter.

3. Semiconductors

In the field of semiconductors, antimony is valued for its ability to provide n-type conductivity. Antimony compounds, particularly antimony telluride, are used in thermoelectric devices for converting waste heat into electricity, offering a sustainable way to generate power.

4. Medicine

Antimony compounds have historical significance in medicine. Antimony potassium tartrate, once used as an emetic, highlights antimony’s limited but notable role in pharmaceuticals. Modern research is exploring antimony’s potential in treating parasitic diseases like leishmaniasis.

5. Pigments

Antimony salts are used to create pigments for paints, plastics, and ceramics. The most common pigment made from antimony is antimony white (antimony oxide), which provides a white coloration and opacity to products.

Commercial Production of Antimony

The commercial production of antimony involves several key steps. The majority of antimony is extracted from its ores, mainly stibnite (Sb₂S₃), which contains up to 71% antimony.

1. Mining and Extraction: The first step involves mining stibnite ore, which is then subjected to a flotation process. This process separates the antimony sulfide from the waste rock or impurities.
2. Roasting: The antimony sulfide is roasted in air to convert it into antimony oxide (Sb₂O₃).
3. Reduction: The antimony oxide is then reduced to metallic antimony by heating it with carbon or by reacting it with iron scrap in a blast furnace.
4. Refining: The crude antimony is further refined to remove impurities. This is typically done through electrolytic refining or by treating the antimony with oxygen-rich air to remove remaining sulfur and lead.
5. Formation of Antimony Products: Finally, the refined antimony is processed into alloys, compounds, and various products depending on its intended use.

Throughout this process, environmental and safety considerations are crucial due to the toxic nature of some antimony compounds. The production facilities are designed to minimize any adverse environmental impact and ensure the safety of workers handling these compounds.

Health Effects of Antimony

Antimony, a metalloid, can have various health effects depending on the exposure level and form of antimony. Here are some key points:

1. Respiratory Issues: Inhalation of antimony dust or fumes, often in industrial settings, can lead to respiratory irritation, chronic bronchitis, and even pneumoconiosis (a lung disease caused by inhaling dust).
2. Skin Contact: Direct skin contact with antimony compounds can cause dermatitis and skin irritation. In more severe cases, it can lead to ulcers.
3. Gastrointestinal Problems: Ingesting antimony compounds can lead to gastrointestinal issues such as nausea, vomiting, and abdominal pain.
4. Cardiovascular Effects: Long-term exposure to antimony has been linked to increased risks of cardiovascular problems, including alterations in heart rhythm.
5. Reproductive Health: There is evidence suggesting that antimony exposure can adversely affect reproductive health, potentially causing menstrual irregularities and miscarriages.
6. Cancer Risk: The International Agency for Research on Cancer (IARC) has classified antimony trioxide as a possible human carcinogen, indicating a potential risk of cancer with prolonged exposure.
7. Neurological Effects: Chronic exposure to antimony can lead to headaches, insomnia, and in some cases, dizziness and depression.
8. Immunological Impact: There is some indication that antimony exposure can affect the immune system, though the extent and nature of this impact require further research.

Environmental Effects of Antimony

Antimony’s environmental impact is significant, especially near mining and processing sites. Here’s an overview:

1. Water Contamination: Antimony can leach into water bodies from industrial processes, leading to contamination. This is particularly concerning for aquatic life.
2. Soil Contamination: Antimony compounds can accumulate in soils, especially near industrial areas, affecting soil quality and potentially entering the food chain.
3. Air Pollution: Antimony trioxide and other compounds, when airborne, contribute to air pollution. This is a concern for both environmental and human health.
4. Impact on Aquatic Life: Antimony in water bodies can be toxic to fish and other aquatic organisms, affecting their growth, reproduction, and survival.
5. Bioaccumulation: Antimony can bioaccumulate in plants and animals, leading to higher concentrations in organisms higher up in the food chain.
6. Effect on Plant Growth: High concentrations of antimony in soil can inhibit plant growth and can cause phytotoxicity.
7. Long-Term Persistence: Antimony compounds can persist in the environment for long periods, leading to prolonged exposure risks for both wildlife and humans.
8. Waste Management Challenges: The disposal of antimony-containing waste requires careful handling due to its toxic nature, posing challenges in waste management and recycling processes.

What is Antimony Used For?

Antimony is primarily used in alloys, flame retardants, plastics, and electronics, enhancing durability and fire resistance.

Is Antimony Harmful to Humans?

Excessive exposure to antimony can be toxic, potentially causing respiratory, skin, and cardiovascular issues.

What Everyday Products Contain Antimony?

Common products containing antimony include batteries, flame-resistant materials, ceramics, glass, and some cosmetics.

What is the Old Name for Antimony?

The old name for antimony is “Stibium,” symbolized as ‘Sb’ in the periodic table.

What Happens if You Touch Antimony?

Touching antimony typically poses minimal risk, but prolonged contact can cause skin irritation.

What is the Source of Antimony?

Antimony is mainly sourced from stibnite ore and as a byproduct of lead and copper smelting.

Antimony’s unique properties make it invaluable in numerous applications, from fire retardants to alloys. However, handling it requires caution due to its potential toxicity. Balancing its industrial benefits with health and environmental considerations is essential for its sustainable and safe use.