"四价钛的" can be translated as "tetravalent titanium (related/pertaining to)" or "of tetravalent titanium" in English, depending on the context.
If you're referring to a property, compound, or characteristic associated with tetravalent titanium, you might say "tetravalent titanium property/compound/characteristic."
If you're using it as an adjective to describe something, you could say "of tetravalent titanium," such as in "the behavior of tetravalent titanium compounds."
In simpler or more direct translations, especially when naming specific substances or in chemical contexts, you might just say "tetravalent titanium" followed by the relevant noun (e.g., "tetravalent titanium oxide").