Crystal structure of a chloride-bridged copper(II) dimer: piperazine-1,4-dium bis(di-μ-chlorido-bis[(4-carboxypyridine-2-carboxylato-κ<sup>2</sup><i>N</i>,<i>O</i><sup>2</sup>)chloridocuprate(II)]
Acta crystallographica. Section E, Crystallographic communications