What is it about light mineral oil or glass that allows praseodymium to an excellent source for storing?

Question

What is it about mineral oil or glass that makes it a good source for storing praseodymium?

Background info:

Praseodymium is a soft silvery metal in the lanthanide group. It is somewhat more resistant to corrosion in air than europium, lanthanum, cerium, or neodymium, but it does develop a green oxide coating that spalls off when exposed to air, exposing more metal to oxidation. For this reason, praseodymium should be stored under a light mineral oil or sealed in glass.

Answer 1

Mineral oil and glass can keep air and water away from the praseodymium.  The metal will react easily with air and water, as your background info notes.

As for why they don't react with the metal, glass contains oxygen bound to silicon.  Silicon is easily oxidized (electropositive), and so it takes much energy to remove the oxygen from the silicon.  Praseodymium is reactive enough to reduce glass if heated strongly with it though...

Mineral oil consists of hydrocarbons, so there is no oxygen to react with.