Selenium: Long-Chain Semiconductors, Photo Sensors, and Shampoos | Periodic Videos

Overview

In this Periodic Videos segment, selenium is introduced as an element closely related to sulfur, but typically forming long chain arrangements. The video explains how shining light on these selenium chains can make them conduct electricity, a property that helped selenium be used in early photo sensors for security systems like burglar alarms and auto-opening doors.

• Selenium forms long chain structures and acts as a semiconductor
• Early photo sensors were built using selenium
• Selenium is also used as a dietary supplement
• Selenium compounds in shampoos can kill bacteria that cause dandruff
• Body odor concerns arise from selenium compounds and tellurium is described as worse

Introduction to Selenium

The video frames selenium as an element similar to sulfur, noting its common form as long chains rather than S8 rings. It highlights how light can enable conduction in these chains, linking this behavior to early selenium-based photo sensors used in burglar alarms and automatic doors.

Applications and History

Beyond electronics, selenium has diverse uses, including its role in shampoos where compounds that combine sulfur and selenium act as bactericides to combat dandruff. The host presents a vivid sample of selenium and remarks on its striking black appearance, emphasizing its practical value as a mineral with wide applications.

Safety and Odor Considerations

The discussion turns to health, noting that while selenium is taken as a dietary additive, some selenium compounds produce odorful sulfide-like compounds when present in the body. The presenter also jokes that selenium chemists can evoke scent effects on a bus, and mentions tellurium as even more odorous in comparison.