Question

Why is osmium tetroxide very expensive and highly toxic?

Answer 1

Osmium tetroxide is expensive because osmium is a rare element.

Cost

Osmium is one of the rarest elements in the Earth's crust.

Osmium is obtained as a by-product from nickel and copper processing. It has to be separated from Ru, Rh, and Ir and then converted to OsO₄. This all costs money.

The US production of Os is probably only about 75 kg/year.

Toxicity

Osmium tetroxide is highly toxic, but its mechanism of action is unknown.

OsO₄ can enter the body by ingestion or by inhalation of its vapor or aerosol.

It is a severe irritant of the eyes, skin, and respiratory tract.

Skin burns result in blisters or skin discoloration.

Ingestion can lead to burning sensation, cramps, collapse, or shock.