- It does not oxidize easily in air unless it is heated.
- When heated it forms osmium tetroxide, which is very toxic.
- It is not affected by most acids.
- It is found in platinum ores and in a mineral called osmiridium,
which is very rare.
- It is also a byproduct of refining nickel ores mined in the
Sudbury Basin, Ontario, Canada.
- It has the highest melting point and the lowest vapor pressure of the platinum elements.