The title three-dimensional coordination network. {[Er(C4H4N2O2)4](ClO4)3}n. is isostructural to that of other lanthanides. The Er+3 cation lies on a fourfold roto-inversion axis. https://www.diegojavierfares.com/mega-choice-Seattle-Seahawks-NFL-Printed-Camo-Socks-p11205-top-buy/