Barium

Chemical reactions

Reaction of barium with acids


Barium reacts with hydrochloric acid, forming BaCl2 [7].

Ba(s) + 2 HCl(aq) BaCl2(aq) + H2(g)


Reaction of barium with air


Barium reacts with oxygen when exposed to air, forming a thin passivating layer of BaO on the surface. When ingnited, barium reacts with both oxygen and nitrogen, forming a mixture of BaO, Ba3N2 and BaO2.

2 Ba(s) + O2(g) 2 BaO(s)
Ba(s) + O2(g) BaO2(s)
3 Ba(s) + N2(g) Ba3N2(s)


Reaction of barium with carbonate


Ba (II) is precipitated by carbonate ions as BaCO3

Ba2+(aq) + CO32−(aq) BaCO3(s)


Reaction of barium with chromate


Ba (II) is precipitated by chromate ions under alkaline, neutral and acetic acid conditions as BaCrO4 (yellow precipitate)

Ba2+(aq) + CrO42−(aq) BaCrO4(s)


Reaction of barium with hydrogen


Barium reacts with hydrogen, forming barium hydride [7].

Ba(s) + H2(g) BaH2(s)


Reaction of barium with hydroxide ions


Ba(II) is not precipitated by hydroxide as Ba(OH)2, (S[Ba(OH)2] = 4g/100 ml @ 20 °C)


Reaction of barium with oxalate


Ba (II) is precipitated by oxalate as Ba2O4 (white precipitate)

Ba2+(aq) + C2O42−(aq) BaC2O4(s)


Reaction of barium with sulfate


Ba (II) is precipitated by sulfate ions under neutral and acidic conditions as BaSO4 (white precipitate)

Ba2+(aq) + SO42−(aq) BaSO4(s), L[BaSO4] = 10-10 M²


Reaction of barium with sulfide


Ba(II) is not precipitated by sulfide


Reaction of barium with water


Barium reacts readily with water, forming barium hydroxide, Ba(OH)2 and hydrogen (H2).

Ba(s) + 2 H2O(g) Ba(OH)2(aq) + H2(g)


Quantitative analysis


Method 3500-Ba C Inductively Coupled Plasma Method [6]. 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