What is the configuration of dimethyl[tris(trifluoromethyl)]-λ⁵-phosphane?
You can note that $\ce{-CH3}$ shows electron releasing (+I) effect while $\ce{-CF3}$ shows strong electron withdrawing effect. Now, you can treat inductive effect as the organic analogue of electronegativity, giving axial positions to $\ce{-CF3}$  and equatorial ones to $-\ce{CH3}$ in accordance with Bent's rule.