Sodium iodide

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Sodium iodide
Names
IUPAC name
Sodium iodide
Other names
Sodium monoiodide
Properties
NaI
Molar mass 149.89 g/mol
Appearance White solid
Odor Odorless
Density 3.67 g/cm3
Melting point 661 °C (1,222 °F; 934 K)
Boiling point 1,304 °C (2,379 °F; 1,577 K)
158.7 g/100 ml (0 °C)
184.2 g/100 ml (25 °C)
227.8 g/100 ml (50 °C)
294 g/100 ml (70 °C)
302 g/100 ml (100 °C)
Solubility Reacts with sulfuric acid
Soluble in acetone, acetonitrile, ethanol, formamide, formic acid, isopropanol, methanol
Slightly soluble in dimethylformamide, liq. sulfur dioxide
Insoluble in halocarbons, hydrocarbons
Solubility in acetamide 32.3 g/100 g (41.5 °C)
Solubility in acetone 50.4425 g/100 g (25 °C)
Solubility in acetonitrile 24.9 g/100 g (25 °C)
Solubility in ammonia 162 g/100 g (25 °C)
Solubility in dichloromethane 0.009 g/100 g (25 °C)
Vapor pressure ~0 mmHg
Thermochemistry
91 J·mol−1·K−1
−288 kJ·mol−1
Hazards
Safety data sheet Sigma-Aldrich
Flash point Non-flammable
Lethal dose or concentration (LD, LC):
4.340 mg/kg (rat, oral)
Related compounds
Related compounds
Potassium iodide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Sodium iodide (NaI) is a chemical compound, a salt formed from sodium and iodine.

Properties

Chemical

Addition of a strong acid, like sulfuric acid will form hydroiodic acid, which decomposes to liberate elemental iodine.

2 NaI + H2SO4 → Na2SO4 + 2 HI
2 HI → H2 + I2

Physical

Sodium iodide is a colorless odorless solid, soluble in water.

Availability

Sodium iodide is sold by chemical suppliers.

Preparation

Can be made by neutralizing hydroiodic acid with sodium hydroxide/carbonate/bicarbonate:

NaOH + HI → NaI + H2O
Na2CO3 + 2 HI → 2 NaI + H2O + CO2
NaHCO3 + HI → NaI + H2O + CO2

Another route is addition of iodine to sodium thiosulfate.

2 Na2S2O3 + I2 → 2 NaI + Na2S4O6

Projects

Handling

Safety

Sodium iodide has low toxicity.

Storage

Sodium iodide should be kept in closed bottles, plastic or glass.

Disposal

Can be recycled or dumped in trash.

References

Relevant Sciencemadness threads