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All 118 elements

Element 61 ·lanthanide

pǒ — "promethium"

Promethium

Traditional:

How the character is built

The radical marks this as a metal, and that is not a coincidence of this one character — it holds right across the table. Read the radical first and the element's state at room temperature is already settled. It is (jīn) squeezed into the space beside another component — radicals change shape by position, which is why is hard to spot until you know to look for .

Phonetic 叵 pǒ, a character rare enough that 钷 has essentially no other use.

This character is used for the element and little else — you are unlikely to meet it outside a chemistry classroom.

The element itself

Promethium is the hole in the lanthanides. Every one of its isotopes is radioactive with a short enough half-life that essentially none survives from the formation of the Earth, so unlike its neighbours it cannot simply be dug up — the tiny natural quantity that exists is generated continuously by uranium decay and amounts to a few hundred grams in the whole crust. It was finally identified among the fission products of a reactor, and named for the Titan who stole fire, which for an element born in a reactor is not a bad choice.

Where it sits among the 118

Promethium melts at 1042°C (1315 K) — lower than 42 of the 97 elements whose melting point has been measured, and higher than 54. The grey dots are the rest of the table.
In the Earth's crust there is present only in traces, far below a milligram per tonne. That makes it commoner than 2 of the 93 elements that occur naturally at all. The scale is logarithmic: each gridline is ten times the one below it.

First isolated in 1945.

The full entry

For stroke order, example sentences, audio and the complete set of meanings, see the dictionary entry.

Promethium in the dictionary →

Others built the same way

Every one of these carries , and every one is a metal.

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