Is pure osmium poisonous?
Osmium, the densest pure metal. Is it poisonous?
Pure osmium is volatile and very toxic. This means it is highly poisonous and this makes it an unappealing reagent to use in stoichiometric amounts. For more detailed information, go to http://www.chemicool.com/elements/osmium.html.
In its natural state, no. When a compound, yes!