Lanthanum Atomic number 57 Hidden stuff Commentary

Stockholm—Carl Gustaf Mosander elements

Lanthanum

• Carl Gustof Mosander found,
• lying hidden in a sample of cerite,
• an oxide of a new rare earth, which
• he named “that which lies hidden.”
• Little did he know that lying hidden
• in “that which lies hidden” were five
• other rare earths—gadolinium, praseodymium,
• neodymium, samarium, and europium.

Atomic number 57

• Lanthanum is used
• in steel alloys
• and molybdenum alloys.
• Mischmetal of lanthanum
• and other rare earths
• are in the anode
• of nickel-metal hydride batteries
• and in lighter flints.
• Lanthanum oxide is in
• vacuum-tube emitters
• glass that resists alkali,
• glass that absorbs infrared,
• glass for camera and telescope lenses,
• and electrodes for gas tungsten arc welding.

Hidden stuff

• A lurking suspicion.
• A recessive gene
• causing a bias
• an unexpected response.
• A hidden pattern.
• An unexplained secret.
• A mystery, an enigma.
• The element of surprise.