[Verse 1] Fourteen seats at the four-f table, tucked inside the core, Five-s, five-p stand guard like curtains drawn before the door. That's why the valence barely shifts from cerium to loot, Three-plus is the uniform, the house style, the family suit. Buried orbitals, obedient ions, calm and unafraid, Chemistry stays quiet while the outer shell's the one displayed. [Chorus] La-Lu, plus-three, that's the law of the land, Cerium tips to four, the outlier, understand. Europium, ytterbium, borrow two and hide, Half-full, all-full, stability's their guide. Sing it: core electrons, spectra thin and sharp, Shielded from the lattice, plucking a hidden harp. [Verse 2] Ask me why the color's faint, why the bands run narrow— Laporte says the f-to-f jump's forbidden, thin as marrow. Outer shells absorb the shake, the phonons can't get in, So the lines stay razor sharp beneath the lanthanide skin. Compare a transition metal, d-orbitals exposed and raw, Ligands rattle, bands go broad, that's the crystal field law. Cerium sheds a fourth electron, chasing xenon's rest, Europium and ytterbium grab one back, half-full, full nest— Four-f-seven, four-f-fourteen, symmetric, calm, complete, Chatoyant shimmer in the phosphor, luminescent, bittersweet. [Chorus] [Verse 3] Neodymium-iron-boron, magnets ripping steel like paper, Samarium-cobalt holds its heat when engines run the caper. Gadolinium, three-plus, seven lone electrons spin, Slips into your bloodstream, lights the MRI within. Dig the ore in Baotou, Bayan Obo's toxic clay, Thorium tailings, acid ponds, the price the landscapes pay. Solvent extraction, ion exchange, patience drop by drop— Fourteen cousins look alike, the sorting will not stop. [Verse 4] Cross to actinium's family, five-f orbitals run wide, Diffuse and restless, mixing with the six-d, side by side. Uranium climbs from three to six, plutonium's a shapeshifter too, Seven phases in one metal, an alloy's nightmare stew. Uranyl ion, oxygen-uranium-oxygen, linear and lean, Swims through reactors, tints the water an eerie uranium green. Enrich it, fission it, reprocess what remains, Vitrify the waste in glass, bury the radiotoxic stains. [Bridge] One atom at a time, cyclotron whispers, recondite and rare, Berkelium, einsteinium, born in a puff of air. Half-lives ticking faster than the sentence can be read— Chase the fleeting isotope before the signal's dead. [Chorus] [Outro] Four-f buried, five-f bold, that's the split we trace, Lanthanide calm, actinide storm, two halves of one strange space.
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