# @stem_antics on Instagram

- **Type:** Video
- **Original URL:** https://www.instagram.com/p/DdsfB5vANMI
- **Gondola URL:** https://gondola.cc/posts/70844135-stem-antics-instagram
- **Thumbnail:** https://img.gondola.cc/tr:w-,h-,fo-auto/postThumbnails/75c01f4e32.jpg
- **Posted:** 2026-09-25T03:23:38.000+00:00
- **Account Owner:** Stem Antics (@stem_antics) — https://gondola.cc/stem_antics

## Caption

Lithium does not simply burn. It moves through a sequence of distinct physical and chemical stages, and each one is written in colour.

Hold a sliver of lithium metal in a flame and the first thing to disappear is the silver lustre. The surface tarnishes almost instantly into a dark crust of lithium nitride and lithium oxide. Lithium is the only alkali metal that reacts with atmospheric nitrogen at room temperature, so the air itself attacks it before any fire is involved.

The progression unfolds in stages:

- Melting at 180.5 °C, where the metal collapses into a bright liquid bead
- Ignition, where the bead sustains a vivid crimson flame
- Full combustion, where the flame shifts to an intense white as solid Li2O particles incandesce
- Burnout, leaving a pale oxide residue behind

The crimson is atomic, not thermal. Heat promotes lithium’s single 2s valence electron into the 2p orbital. When it relaxes, it emits a photon at 670.8 nm, deep in the red. That single dominant line is why lithium reads crimson, while sodium, with its 589 nm doublet, glows yellow-orange.

The white stage is different physics entirely. Once combustion becomes vigorous, the flame fills with microscopic oxide particles heated to extreme temperatures. They radiate as near-blackbody emitters across the whole visible spectrum, washing the red line out into brilliant white. One colour is quantum mechanics; the other is thermal radiation.

Johan August Arfwedson identified lithium in 1817 while analysing the mineral petalite in the laboratory of Jöns Jacob Berzelius. In 1860, Robert Bunsen and Gustav Kirchhoff used that same red emission line to help establish flame spectroscopy as an analytical discipline.

The colour of a flame is a fingerprint of the electron that made it.

#stemantics #chemistry #lithium #spectroscopy #materialsscience

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## Tags

materialsscience, chemistry, spectroscopy, stemantics, lithium

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