What is "perchloratoborate"

Perchloratoborate is an anion of the form [B(ClO)]. It can form partly stable solid salts with heavy alkali metals. They are more stable than nitratoborate salts. K[B(ClO)] decomposes at 35 °C, Rb[B(ClO)] is stable to 50 °C, and Cs[B(ClO)] can exist up to 80 °C.

Perchloratoborates are analogous to perchloratoaluminates ([Al(ClO)]).

Another related anion is the chloroperchloratoborate, ClB(ClO).

Boron perchlorate itself is unstable above –5 °C.