Tantalum

Tantalus, the son of the Greek god Zeus is the namesake for the element tantalum. The name should allude “to the inability of the element tantalum to get at the material when it is immersed in a surplus of acid and is saturated by it”

In fact, tantalum is extremely resistant to corrosion and thus resistant to most acids and alkalis.

Almost identical atomic and ion radii with analogous occupation of the outer electron shells make tantalum very similar to niobium.