Strontium

Chemical reactions

Reaction of strontium with acids


Strontium dissolves readily hydrochloric acid, forming Sr(II) ions and hydrogen gas, H2.

Sr(s) + 2 HCl(aq) Sr2+(aq) + 2 Cl−(aq) + H2(g)


Reaction of strontium with air


Strontium reacts with oxygen, O2, forming a protective layer of SrO on the surface. When burned, strontium reacts with both oxygen and nitrogen, N2:

2 Sr(s) + O2(g) 2 SrO(s)
3 Sr(s) + N2(g) 2 Sr3N2(s)


Reaction of strontium with carbonate


Sr(II) is precipitated by carbonate ions.

Sr2+(aq) + CO32−(aq) SrCO3(s)

The carbonate is a white crystalline precipitate that easily dissolves in acid

SrCO3(s) + NH4+(aq) Sr2+(aq) + HCO3−(aq) + NH3(aq).


Reaction of strontium with chromate


Sr(II) is not precipitated by chromate ions in acetic acid..


Reaction of strontium with halogens


Strontium reacts with chlorine, Cl2, bromine, Br2, and iodine, I2, forming the corresponding Sr(II) halides. The reactions with bromine and iodine requires heat:

Sr(s) + Cl2(g) SrCl2(s)
Sr(s) + Br2(g) SrBr2(s)
Sr(s) + I2(g) SrI2(s)


Reaction of strontium with hydrogen


Strontium reacts with hydrogen, forming strontium hydride [6].

Sr(s) + H2(g) SrH2(s)


Reaction of strontium with hydroxide ions


Sr(II) is not precipitated by OH− (S[Sr(OH)2] = 0.8 g/100 ml @ 20 °C).


Reaction of strontium with oxalate


Sr(II) is precipitated by ammonium oxalate

Sr2+(aq) + C2O42−(aq) SrC2O4(s)

The oxalate is a white crystalline precipitate that dissolves in mineral acids

SrC2O4(s) + 2 H+(aq) Sr2+(aq) + H2C2O4(aq).


Reaction of strontium with sulfate


Sr(II) is precipitated by sulfate ions at neutral or slightly acidic solutions. The sulfate is a white crystalline precipitate.

Sr2+(aq) + SO42−(aq) SrSO4(s)

In strong acidic solutions SrSO4 dissolves as the sulfate concentration becomes to small:

SO42−(aq) + H+(aq) HSO4−(aq), L[SrSO4] = 4·10-7 M2.


Reaction of strontium with sulfide


Sr(II) does not precipitated by H2S or sulfide ions in acidic or alkaline solutions.


Reaction of strontium with water


Strontium reacts slowly with water, forming strontium hydroxide, Sr(OH)2 and hydrogen gas, H2.

Sr(s) + 2 H2O(l) Sr(OH)2(aq) + H2(g)


Quantitative analysis


Method 3500-Sr C Inductively Coupled Plasma Method [2]. A portion of the sample is digested in a combination of acids. The digest is aspirated into an 8,000 K argon plasma where resulting light emission is quantified for 30 elements simultaneously.

Method limit of detection in water = 0.002 mg/L
Method limit of detection in soil = 1.00 mg/kg.