How the character is built
The 钅 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 金 (jīn) squeezed into the space beside another component — radicals change shape by position, which is why 金 is hard to spot until you know to look for 钅.
Where you actually meet it
低钠盐 (dīnàyán) low-sodium salt
The element itself
Sodium metal is soft, silvery for about a second, and violent in water, which makes its everyday form — half of table salt — seem like a different substance entirely. The world's salt sits in beds left by seas that dried up, sometimes hundreds of metres thick, and because rock salt is less dense than the sediment piled on top of it and flows slowly under pressure, it rises in great columns called salt domes. Those domes push and warp the layers around them, and the traps they create are where a good deal of the world's oil ended up.
Where it sits among the 118
First isolated in 1807.
In living things
Sodium is the body's outside ion, kept high in the fluid between cells and low within them by a pump that shoves three sodium ions out for every two potassium in, burning one ATP each cycle. It is an enormous running cost — a large share of a resting cell's energy, and in the brain something like half the total — but what the cell buys is a battery. Other transporters ride the sodium gradient like a waterwheel: glucose and amino acids are dragged into the gut lining against their own concentration simply by coupling them to sodium falling back in, which is the mechanism behind rehydration mixtures that pair salt with sugar rather than using either alone.
In Chinese history and language
The salt monopoly is among the oldest continuously reinvented institutions in Chinese history: the state took 盐 yán because everyone must buy it, and the argument over whether it should have was staged at court in 81 BCE and written up a generation later as the 盐铁论 Yántiělùn, the Discourses on Salt and Iron, which still reads like a live debate about state enterprise. Landlocked Sichuan got its salt from underground brine, and pumping it produced a drilling tradition of its own — hand-sunk wells from the Warring States, bamboo-cased percussion drilling by the Song, and in 1835 a well at 自贡 Zìgòng that passed a kilometre, the deepest hole yet made anywhere. The natural gas that came up with the brine was piped in bamboo and burned under the evaporation pans.
Where it comes from in China
For salt, the place is the Sichuan basin, where brine — ancient seawater trapped in rock — is pumped from wells rather than raked from coastal pans. The drilling is the remarkable part: from the 1040s, in the Northern Song, Sichuan well-diggers were sinking narrow percussion-drilled boreholes cased with bamboo tubing, lifting and dropping a heavy iron bit on a rope, over and over. Depths crept downward across roughly eight centuries until, in 1835, a well at Zigong passed a thousand metres — the first anywhere to do so, drilled with bamboo, rope and muscle alone. The wells often struck natural gas alongside the brine, and it was piped, again in bamboo, to fire the pans that boiled the brine down to salt.
The full entry
For stroke order, example sentences, audio and the complete set of meanings, see the dictionary entry.
钠Sodium in the dictionary →Others built the same way
Every one of these carries 钅, and every one is a metal.