What metals have unpredictable properties?

Metals such as titanium, zirconium, and certain rare earth metals can exhibit unpredictable properties due to their complex electronic structures and varying oxidation states. Additionally, transition metals like manganese and chromium can show unexpected behavior in different alloys or under varying environmental conditions. The properties of these metals can change significantly based on factors like temperature, pressure, and chemical composition, leading to challenges in their application and processing.