What is Lanthanum?

Lanthanum, the fifty-seventh element on the periodic table, is a soft, silvery lanthanide. It kicks off the rare earth series and shines in modern tech.

Atomic Number: 57

Symbol: La

Atomic Mass: 138.91 u

Category: Lanthanide

State at Room Temperature: Solid

Discovered By: Carl Gustaf Mosander (1839)

⚛️ Atomic Structure of Lanthanum

Lanthanum has fifty-seven protons, eighty-two neutrons (in its most common isotope, Lanthanum-139), and fifty-seven electrons, with three in its outer shell.

  • 🟢 Protons: 57
  • 🔴 Neutrons: 82 (Most common isotope, Lanthanum-139)
  • 🟡 Electrons: 57

💡 Did you know? Lanthanum's softness lets you cut it with a knife!

🔬 Lanthanum Properties

Lanthanum is soft, malleable, and reactive. It melts at 920°C (1688°F) and tarnishes in air, forming an oxide layer.

🧬 How Was Lanthanum Discovered?

In 1839, Swedish chemist Carl Gustaf Mosander isolated Lanthanum from cerium nitrate, naming it from Greek "lanthanein" (to lie hidden) due to its elusive nature.

⚡ Uses of Lanthanum

  • 🔋 Batteries: Nickel-metal hydride batteries.
  • 🔍 Optics: High-quality lenses and glass.
  • 💡 Lighting: Carbon arc lamps for studios.
  • 🔬 Catalysts: Petroleum refining.

💡 Fun Facts About Lanthanum

  • 🧀 So soft it's like cheese.
  • 🌍 First of the rare earths.
  • 🔥 Ignites in air if finely divided.
  • 🎥 Used in Hollywood lighting.

⚠️ Safety & Precautions

Lanthanum is reactive and can ignite in powder form. It's mildly toxic if ingested; handle with gloves, avoid dust inhalation, and store away from moisture.

🔬 Explore More Elements