Strontium
Element 38 · Alkaline Earth Metal
Strontium is a typical group 2 metal: silvery when freshly cut, quick to tarnish in air, and eager to lose its two outer electrons to form the Sr²⁺ ion. It is far less dramatic than its alkali-metal neighbors, but it owns one of the most vivid signatures in chemistry — strontium salts color flames a deep crimson red, the reason fireworks and emergency flares glow red. The metal itself is soft and malleable, and its chemistry closely mirrors calcium, which is why small amounts of strontium naturally end up in human bones and teeth.
Key facts
| Atomic number | 38 |
|---|---|
| Atomic weight | 87.62 |
| Category | Alkaline Earth Metal |
| Group / Period | 2 / 5 |
| Block | s |
| Electron configuration | [Kr] 5s2 |
| Common oxidation states | +2 |
| State at STP | Solid |
| Electronegativity | 0.95 |
| Atomic radius | 215 pm (empirical) |
| Density | 2.64 g/cm³ |
| Melting point | 777 °C |
| Boiling point | 1377 °C |
Occurrence
Strontium is the 15th most abundant element in Earth's crust. It is mined mainly from two minerals: celestite (strontium sulfate) and strontianite (strontium carbonate), and it also occurs dissolved in seawater.
Applications
Fireworks and signal flares (red color)
Ferrite magnets for motors and speakers
Toothpaste for sensitive teeth
Pyrotechnic formulations
Common compounds
- Strontium carbonate
- Strontium nitrate
- Strontium chloride
- Strontium titanate
Strontium is named after Strontian, the Scottish village where its ore was first identified — one of the few elements named for a place in Britain.
Data source: IUPAC standard atomic weights 2021; NIST physical property data