Strontium (Sr)

Soft, silvery metal

Strontium is the metal that makes fireworks explode in brilliant red and is found in your toothpaste, and with a filled 5s² shell, strontium's emission spectrum produces deep red light (650-700 nm). Strontium-90, a fission product, accumulates in bones and strontium ranelate is used to treat osteoporosis.

Key metrics

Density2.64g/cm³

Melting point1,050K

Boiling point1,655K

Electronegativity0.95Pauling

Discovery

1790discovered

Discovered by: Adair Crawford
Reactivity profile: Reacts with air and water
Reactivity: High
Bonding: Metallic

Electron configuration

\textcolor{#6b7280}{[Kr]}\; \textcolor{#ef4444}{5_{s}^{2}}

[Kr] 5s2

Wave function

\Psi_{\text{Sr}} \approx \frac{1}{\sqrt{38!}} \det \left| \chi_1(\mathbf{r}_1) \dots \chi_{38}(\mathbf{r}_{38}) \right|

Probability density $|\Psi|^2$ across the Sr valence shell.

Crystal structure

Face-Centered Cubic

Lattice constantsa = 1.00

Cell anglesα = β = γ = 90°

Coordination number12

Atoms per cell4

Atomic packing factor0.74

Physical properties

Atomic radius: 219 pm
Ionization energy: 550 kJ/mol
Electron affinity: 5 kJ/mol
Crystal structure: Face-centered cubic (fcc)

Oxidation states

Acid/base

Basic

Strongly acidicStrongly basic

State at 25 °CSolid

1050 K1655 K298 K

Emission spectrum

3 transitions

380450500550600650700780

VioletBlueGreenYellowRed

460.7nmSr I (blue)Blue100%

496.2nmSr ICyan40%

707.0nmSr I (red)IR60%

Dominant line 460.7 nmRange 461–707 nmTransitions 3