======Allotropes of Sulfur======


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**Alternative titles:** Polymeric Sulfur Demonstration, Polymeric Sulfur
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====Summary====                   
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====Procedure====  
  - Place powdered sulfur in a heat-resistant container and gently heat it.  
  - Observe as the yellow solid melts into a brown liquid that initially flows easily.  
  - Continue heating and note how the liquid becomes increasingly viscous, indicating the formation of long-chain polymeric sulfur.  
  - On further heating, the sulfur flows more freely again, but may ignite with a blue flame.  
  - Carefully pour the burning sulfur into a beaker of cold water.  
  - Once cooled, remove the solidified sulfur from the water. Observe that it is rubbery and flexible, distinct from crystalline sulfur.



====Links==== 
Experiments with Sulphur - Adrian's Chemistry Laboratory: 
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Sulfur Spaghettio Demonstration - MrLundScience: 
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📄 Plastic Sulfur - Chemistry Comes Alive!: [[https://www.chemedx.org/JCESoft/jcesoftSubscriber/CCA/CCA2/MAIN/PLASULF/CD2R1.HTM]]\\


====Variations====
  * Compare cooled sulfur quenched in water versus sulfur allowed to cool slowly in air (which recrystallizes and becomes brittle).  
  * Use different cooling methods (ice bath vs. room temperature water) to test how quickly cooling affects the polymeric structure.  
  * Break apart quenched sulfur samples after some time to observe how they revert back to the brittle crystalline form.



====Safety Precautions====
  * Safety glasses and lab coat required.  
  * Perform in a fume hood or well-ventilated area — burning sulfur releases sulfur dioxide, an irritating gas.  
  * Handle hot liquids with care to avoid burns.  
  * Keep a fire extinguisher nearby.  
  * Dispose of sulfur waste according to local regulations.




====Questions to Consider====
  * Why does molten sulfur first become viscous and then flow more freely again? (Polymer chains form and then break down at higher temperatures.)  
  * What is the difference between polymeric sulfur and crystalline sulfur? (Polymeric sulfur is rubbery and flexible; crystalline sulfur is brittle and yellow.)  
  * Why does quenched sulfur slowly revert back to the brittle form? (Polymeric sulfur is metastable and gradually reorganizes into the stable crystalline form.)  
  * What type of chemical change occurs when sulfur ignites? (A combustion reaction forming sulfur dioxide gas.)