The number of species below that have two lone pairs of electrons in their central atom is_____ \( \mathrm{SF_4} \), \( \mathrm{BF_4^-} \), \( \mathrm{ClF_3} \), \( \mathrm{AsF_3} \), \( \mathrm{PCl_5} \), \( \mathrm{BrF_5} \), \( \mathrm{XeF_4} \), \( \mathrm{SF_6} \)
