Compounds | Reactions | Production
|
Reactions of Arsenic |
Reactions with water |
Arsenic does not react with water in the absence of air under normal conditions. |
Reactions with air |
Arsenic is stable in dry air, but the surface oxidizes slowly in moist air to give a bronze tarnish and finally a black covering. When heated in air, arsenic ignites "arsenic trioxide" - actually tetra-arsenic hexaoxide, As4O6. This is accompanied by phosphorescence under some conditions. When heated in oxygen, arsenic ignites to form "arsenic pentoxide" - actually tetra-arsenic decaoxide. |
4As(s) + 5O2(g)As4O10(s) |
4As(s) + 3O2(g)As4O6(s) |
Reactions with halogens |
Arsenic reacts with fluorine to form the gas arsenic(V) fluoride. |
2As(s) + 5F2(g)2AsF5(g) |
Arsenic reacts under controlled conditions with the halogens fluorine, chlorine, bromine and iodine to form arsenic(III) trihalides. |
2As(s) + 3F2(g)2AsF3(l) |
2As(s) + 3Cl2(g)2AsCl3(l) |
2As(s) + 3Br2(g)2AsBr3(l) |
2As(s) + 3I2(g)2AsI3(l) |
Reduction Potentials | |
Balanced half-reaction | E0 / V |
H3AsO4 + 3H+ + 2e-AsO+ + 3H2O | +0.55 |
H3AsO4 + 2H+ + 2e-H3AsO3 + H2O | +0.559 |
H3AsO4 + 2H+ + 2e-H3AsO3 + H2O | +0.577 |
H3AsO4 + 2H+ + 2e-H3AsO3 + H2O | +0.577 |
H3AsO4- + 3H+ + 2e-H3AsO3 + H2O | +0.666 |
H3AsO42- + 4H+ + 2e-H3AsO3 + H2O | +0.881 |
HAsO42- + 3H+ + 2e-H3AsO3- + H2O | +0.609 |
AsO43- + 3H2O + 2e-H3AsO3- + 4OH- | -0.67 |
2H3AsO4 + 4H+ + 4e-As2O3(s) + 5H2O | +0.58 |
2H2AsO4- + 6H+ + 4e-As2O3(s) + 5H2O | +0.687 |
2HAsO42- + 8H+ + 4e-As2O3(s) + 5H2O | +0.901 |
2AsO43- + 10H+ + 4e-As2O3(s) + 5H2O | +1.27 |
AsO43- + 8H+ + 5e-As(s) + 4H2O | +0.648 |
As2O3(s) + 6H+ + 6e-2As(s) + 3H2O | +0.234 |
AsO+ + 2H+ + 3e-As(s) + H2O | +0.254 |
H3AsO3 + 3H+ + 3e-As(s) + 3H2O | +0.248 |
H2AsO3- + 4H+ + 3e-As(s) + 3H2O | +0.429 |
H2AsO3- + H2O + 3e-As(s) + 4OH- | -0.68 |
As(s) + 3H+ + 3e-AsH3(g) | -0.608 |