Here are the structures of SF5 and SF5- - the angle between the axial F and the equatorial Fs in SF5 is 91.2o as we saw in class, and the same angle in SF5- is 84.1o. The bond lengths in SF5 are SFaxial 153.90 pm and Sequatorial 158.55 pm, while in the anion they are 159.69 pm and 169.33 pm respectively. Interesting, isn't it? Can you explain these facts? What would the shape of the SF5 cation be?