Carbon has no melting point at normal pressure — it sublimes

Carbon has no melting point at ordinary atmospheric pressure: heat graphite to about 3,825C (6,917F) and it turns straight from solid to vapour, skipping the liquid stage. The Royal Society of Chemistry’s periodic table lists carbon’s melting point simply as “sublimes at 3825°C”. Carbon is not the only element that skips melting (arsenic sublimes at 616C), but it does so at a far higher temperature.

That is why the familiar claim that tungsten has the highest melting point needs a footnote. Guinness World Records gives tungsten the record among metals while noting that graphite outlasts it: carbon stays solid roughly 400 degrees hotter, then vaporises.

Material and conditions	What happens	Temperature
Arsenic, normal pressure	Sublimes	616C
Tungsten, normal pressure	Melts	about 3,400C
Graphite, normal pressure	Sublimes	about 3,825C
Graphite, about 100 atmospheres	Liquefies	roughly 4,500C

To get liquid carbon you have to squeeze as well as heat. Germany’s Helmholtz-Zentrum Dresden-Rossendorf (HZDR) calls that roughly 4,500C point the highest melting point of any material. No container survives those conditions, so for decades liquid carbon was known mainly from simulations.

An international team led by the University of Rostock and HZDR finally measured it, reporting in Nature in 2025. At the European XFEL near Hamburg, a high-power laser drove compression waves through solid carbon, liquefying it for nanoseconds, while ultrashort X-ray flashes recorded how its atoms were arranged. Repeating the shot many times, with slightly different timing and conditions, built up a movie of the melt. The result: each atom in liquid carbon has four nearest neighbours, much as in solid diamond, and the team narrowed down the melting point where theoretical predictions had diverged. That precision matters beyond curiosity, because liquid carbon exists deep inside planets and plays a part in some concepts for nuclear fusion power.