strontium

• Description
• General information
• Physical data
• Radii
• Electronegativities
• Solid state structure
• Temperatures
• Enthalpies
• Ionization Enthalpies
• Isotopes
• Further information

Description

Strontium does not occur as the free element. Strontium is softer than calcium and decomposes water more vigorously. Freshly cut strontium has a silvery appearance, but rapidly turns a yellowish colour with the formation of the oxide. The finely divided metal ignites spontaneously in air. Volatile strontium salts impart an excellent crimson colour to flames, and these salts are used in pyrotechnics.

Strontium-90 (⁹⁰Sr) has a half-life of 28 years. It is a product of nuclear fallout and presents a major health problem. Strontium titanate is an interesting optical material as it has an extremely high refractive index and an optical dispersion greater than that of diamond. It has been used as a gemstone, but it is very soft.

General information

Discoveror: Adair Crawford
Date discovered: 1790
Discovered at: Scotland
Meaning of name: Named after the village of "Strontian" in Scotland

Physical data

Standard state: solid at 298 K
Colour: silvery white
Density of solid at ambient temperature/kg m^-3: 2630
Molar volume/cm³: 33.94

Radii /pm

Atomic: 219
Covalent (single bond):
Pauling radius for the ion [Sr]^-: no data

Valence shell orbital radius maxima (R_max)

orbital	s	p	d	f
radius	204.5	no data	no data	no data

Electronegativities

Both values are quoted on the Pauling scale.

Pauling: 0.95
Allred Rochow: 0.97

Crystal Structure

structure: ccp (cubic close-packed)

The following CrystalMaker image represents the solid state structure. For most elements, the most stable allotrope is illustrated. Try WebElements version 2 for interactive virtual reality and CHIME images.

Temperatures (/K)

melting point: 1050
boiling point: 1655

Enthalpies /kJ mol^-1

fusion: 7.4
vaporization: 136.9

single bond enthalpies:

Sr-F	Sr-Cl	Sr-Br	Sr-I	Sr-Sr
553	469	405	335	15.5

Ionization enthalpies /kJ mol^-1

Number	Enthalpy
1st	549.5
2nd	1064.2
3rd	4210
4th	5500
5th	6910
6th	8760
7th	10200
8th	11800

Isotopes

This section gives some data for naturally occurring isotopes.

Nominal mass	Accurate mass	% natural abundance
84Sr	83.913430 (4)	0.56 (1)
86Sr	85.9092672 (28)	9.86 (1)
87Sr	86.9088841 (28)	7.00 (1)
88Sr	87.9056188 (28)	82.58 (1)

Further Information

• Additional information about WebElements 1.2.2
• This is a licensed copy (here is the full list) of WebElements 1.2.2 and contains a subset of the material contained within the main version of WebElements (version 2)
• For further information please try WebElements version 2
• Sheffield Chemdex: perhaps the largest internet chemistry directory
• Sheffield Chemputer: interactive chemistry calculators on the WWW