This element violates the octet rule since it has six valence electrons.
An atom of this element is commonly substituted for by a xenon atom in order to make an organic xenon salt. The styx number characterizes a class of compounds named for and containing this element. Sassolite is the mineral form of an acid of this element that can be used to treat conjunctivitis. Clusters incorporating this element form (*) deltahedra cages and often have three-center two electron bonds. Hydrides of this element have banana bonds and come in closo-, nido-, and arachno- types. Wade's rules describe hydrides of this element, whose trifluoride is a strong Lewis acid. This element violates the octet rule since it has six valence electrons. For 10 points, name this element with atomic number 5 and symbol B. 
An atom of this element is commonly substituted for by a xenon atom in order to make an organic xenon salt.
boron