We show that the re are no non-trivial closable derivations of a C*-algebra anticommuting with an ergodic action of a compact group, supposing that the set of squares is dense in the group. We also show that the re are no non-trivial closable densely defined rank one derivations on any C*-algebra.
(1999). Anticommuting Derivations. Proceedings of the American Mathematical Society, 127 (4), 1103-1108.