Substance profile
Methyl iodide
Methyl iodide is colorless, transparent liquid (turns brown on exposure to light) with a pungent, ether-like odor.
01 · Identification
What Methyl iodide is
Methyl iodide is colorless, transparent liquid (turns brown on exposure to light) with a pungent, ether-like odor. It boils at 42.5 °C, melts at -66.5 °C, is miscible with water.
Under the GHS it carries the signal word Danger. It is classed as hazardous Air Pollutants (HAPs).
Other names for Methyl iodide
- iodomethane
02 · GHS classification
Hazards and label elements
Harmonised classification under CLP Annex VI. This is the legally binding classification in the EU; other jurisdictions may differ.
| Code | Hazard statement |
|---|---|
| H351 | Suspected of causing cancer <state route of exposure if it is conclusively proven that no other routes of exposure cause the hazard>. |
| H331 | Toxic if inhaled. |
| H301 | Toxic if swallowed. |
| H312 | Harmful in contact with skin. |
| H335 | May cause respiratory irritation. |
| H315 | Causes skin irritation. |
Precautionary statements: P201, P260, P264, P270, P271, P280, P301, P302, P304, P308, P310, P312, P313, P330, P332, P352
03 · Physical and chemical properties
Methyl iodide properties
Every value is shown with the conditions it was measured under and the source it came from. Where sources disagree, all values are listed rather than one being picked — the difference is usually a different form of the substance, not an error.
| Property | Value | Conditions | Source |
|---|---|---|---|
| Boiling point | 42.5 °C (108.5 °F) | HSDB | |
| 42.78 °C (109 °F) | NIOSH | ||
| 42.39 °C (108.3 °F) | at 760 mmHg | CAMEO | |
| Melting point | -66.5 °C (-87.7 °F) | HSDB | |
| -66.67 °C (-88 °F) | NIOSH | ||
| -66.44 °C (-87.6 °F) | CAMEO | ||
| Density | 2.28 g/cm³ | NIOSH | |
| 2.28 g/cm³ | at 20 °C | HSDB | |
| 2.279 g/cm³ | at 20 °C | CAMEO | |
| Solubility | Miscible with alcohol, ether. | HSDB | |
| Sol in acetone | HSDB | ||
| SOL IN CARBON TETRACHLORIDE | HSDB | ||
| Vapor pressure | 400 mmHg | NIOSH | |
| 661.76 mmHg | CAMEO | ||
| 405 mmHg | at 25 °C | HSDB | |
| Autoignition temperature | 355 °C (671 °F) | ICSC | |
| Lower explosive limit (LEL) | 10 % by volume | CAMEO | |
| 8.5 % by volume | ICSC | ||
| Upper explosive limit (UEL) | 15 % by volume | CAMEO | |
| 66 % by volume | ICSC | ||
| Vapor density | 4.9 (air = 1) | HSDB | |
| Critical temperature and pressure | 254.8 °C (490.6 °F) | HSDB |
Values compiled from PubChem Laboratory Chemical Safety Summary. Temperatures converted to Fahrenheit for reference.
04 · Handling and storage
Storing and handling Methyl iodide
Storage conditions
Keep containers closed and store in a dark place.
Source: Hazardous Substances Data Bank (HSDB)
Incompatible materials
Strong oxidizers [Note: Decomposes at 518 degrees F].
Source: Hazardous Substances Data Bank (HSDB)
Reactivity
Halogenated aliphatic compounds, such as METHYL IODIDE, are moderately or very reactive. Halogenated organics generally become less reactive as more of their hydrogen atoms are replaced with halogen atoms. Low molecular weight haloalkanes are highly flammable and can react with some metals to form dangerous products. Materials in this group are incompatible with strong oxidizing and reducing agents. Also, they are incompatible with many amines, alkylphosphines, nitrides, azo/diazo compounds, alkali metals (sodium), and epoxides.
Source: CAMEO Chemicals
Planning storage for a mix of chemicals? Check Methyl iodide in the storage compatibility matrix →