• General Information:
  • Group: VI
  • Period: 3
  • Atomic Number: 16
  • Electron Configuration: 2.8.6
• Sources:
  • Volcanic regions
  • Crude oil
  • Metal ores
  • Natural gas (H₂S)
• Physical Properties:
  • Brittle yellow substance
  • Crown-shaped molecules (S₈)
  • Insoluble in water, soluble in organic solvents
  • Low melting point
  • Non-conductor of heat and electricity
  • Allotropes: rhombic and monoclinic

• Chemical Properties:
  • Reacts with metals to form sulphides: Mg+S→Mg
  • Burns in oxygen to produce sulphur dioxide: S+O2→SO2
• Uses:
  • Production of sulphuric acid
  • Vulcanizing rubber
  • Making matches, pesticides, drugs, and paper
  • Sulphur concrete
  • Manufacturing gunpowder and plastic flowers

Allotropes of Sulfur

1. Rhombic Sulfur (α-sulfur):
   • Structure: Crystalline form with a yellow color.
   • Properties:
     • Stable at room temperature.
     • Melting point: 112.8 °C.
     • Commonly found in nature.
2. Monoclinic Sulfur (β-sulfur):
   • Structure: Different crystal form that is also yellow.
   • Properties:
     • Stable at higher temperatures (above 96 °C).
     • Melting point: 113.5 °C.
     • Can convert to rhombic sulfur upon cooling.
3. Plastic Sulfur:
   • Structure: Amorphous and rubber-like.
   • Properties:
     • Formed by rapidly cooling molten sulfur.
     • Does not have a definite crystalline structure.
     • Changes to rhombic sulfur over time when exposed to air.
4. Liquid Sulfur:
   • Structure: Exists as a liquid at elevated temperatures.
   • Properties:
     • When heated above its melting point, sulfur becomes a viscous liquid.
     • Can exhibit a range of viscosities based on temperature.

Mechanism of Conversion

• Temperature Influence: The conversion between these two forms is primarily temperature-driven. The stability of each allotrope depends on the temperature:
  • At room temperature, rhombic sulfur is more stable.
  • Above 96 °C, monoclinic sulfur becomes more stable.
• Crystalline Structure: The atoms in each allotrope are arranged differently:
  • Rhombic sulfur has a more compact structure.
  • Monoclinic sulfur has a less compact arrangement, allowing for different physical properties.

Production of Sulphuric Acid

Sulphuric Acid (H₂SO₄) Production Steps (Contact Process):

1. Burning Sulphur:
   • Sulphur is burned in oxygen to produce sulphur dioxide: S(s)+O2(g)→SO2(g)
2. Formation of Sulphur Trioxide:
   • Sulphur dioxide reacts with oxygen to produce sulphur trioxide: SO2(g)+O2(g)→SO3(g)
3. Production of Oleum:
   • Sulphur trioxide is mixed with concentrated sulphuric acid to produce oleum: SO3(g)+H2SO4(l)→H2S2O7(l)
4. Formation of Sulphuric Acid:
   • Oleum is added to water to produce sulphuric acid: H2S2O7(l)+H2O(l)→2H2SO4(l)

Uses of Sulphuric Acid

• Manufacture of inorganic fertilizers (e.g., ammonium sulphate)
• Production of paints and dyes
• Synthesis of synthetic fibers (e.g., nylon)
• Use as an acid in car batteries
• Production of soaps and detergents
• Petroleum refining
• As a dehydrating agent (removes water from other substances)

Primary Method of Obtaining Sulfur: Frasch Process

• Description: The Frasch Process extracts sulfur from underground deposits.

• Process:

  • Superheated water and air are injected into sulfur deposits, melting the sulfur.

  • The molten sulfur is then pumped to the surface.

• Advantages:

  • Efficient for large-scale extraction.

  • Minimizes environmental impact.