Neodymium (Nd)
“The strongest permanent magnets ever made live in your earbuds, your phone’s buzz and every electric car motor — all courtesy of neodymium.”
How its electrons are arranged
Computed from the aufbau principle, with known real-world exceptions applied automatically.
Characteristics
- Electron configuration [Xe] 4f⁴ 6s² — four electrons tucked into the 4f sub-shell, whose unpaired spins make Nd³⁺ a determined little magnet.
- Alloyed with iron and boron it becomes Nd₂Fe₁₄B, the strongest permanent-magnet material known — a coin-sized disc can lift iron hundreds of times its own weight.
- Nd³⁺ salts blush pink, and neodymium glass swaps colour like an outfit — sky-blue in daylight, pink under a filament lamp — a giveaway of its presence.
- Two weaknesses guard its fame: the bare alloy rusts quickly, and heat above roughly 80 °C saps standard grades’ magnetism — hence the nickel plating and heat ratings.
A silvery metal with a faint rose-gold sheen that dulls within minutes in air, so it is kept under oil like its lanthanide cousins. Its favourite costume shows in solution: Nd³⁺ ions blush pink to lavender, and neodymium glass flips between sky-blue, pink and violet as the lighting changes.
Where you meet it
✦ Uses
- Earphone and headphone speakers, phone vibration motors and hard-disk arm positioners — tiny NdFeB magnets that shrink gadgets while raising volume and punch.
- Generators in wind turbines and the drive motors of electric cars, e-bikes and fans — machines that need maximum torque from the least magnet weight.
- Nd:YAG lasers — neodymium-doped crystals firing invisible infrared pulses that cut steel, fix eyes after cataract surgery and range-find distant targets.
- Glass colouring: violet-red neodymium glass for welders’ goggles, premium sunglasses and daylight-mimicking bulbs, plus photographers’ didymium filters.
◍ Everyday examples
- Snap open any broken earphone or dead hard disk: the small, startlingly strong disc magnets inside are NdFeB.
- A bracelet or handbag clasp that snaps shut with unexpected force hides a pair of nickel-plated neodymium magnets.
- Eye hospitals routinely fire Nd:YAG laser pulses to clear the cloudy film that can regrow behind the lens after cataract surgery.
History & name
Neodymium entered chemistry as the other half of Welsbach’s 1885 split of didymium — the twin whose salts came out rose-red instead of green, hence “the new twin”. Pure samples took decades more, and for years the pair were still sold mixed as “didymium” for glass and goggles. The “new” twin then went on to far greater fame: the iron–boron compound Nd₂Fe₁₄B, developed independently by General Motors and Sumitomo in the mid-1980s, became the strongest permanent-magnet material the world has ever known.