Dimer species in aqueous solutions of m–phenylenediamine-N,N,N′,N′-tetra-acetic acid (m-H4pdta) with copper(II) and of pyridine-2,6-diamine-N,N,N′,N′-tetra-acetic acid (2,6-H4pydta) with nickel(II). X-Ray crystal structures of Na4[Cu2(m-pdta)2]·18H2O, Na4[Co2(m-pdta)2]·10H2O, and Na4[Ni2(2,6-pydta)2]·8H2O | Publicación