Osmium (Os) has a variable valency, meaning it can have different valencies depending on the compound it forms.

Here are some of the common valencies for Osmium:

* +2 (e.g., OsO)

* +3 (e.g., OsCl₃)

* +4 (e.g., OsO₂)

* +6 (e.g., OsO₄)

* +8 (e.g., OsO₄)

The most common valencies for Osmium are +4 and +8.