The title complex has been synthesized by the reaction of silicotungstic acid, 1,10-phenanthroline (phen) monohydrate and cupric acetate. The crystal structure belongs to triclinic system, space group P1 with a= 1.15846(15) nm, 6=1.6588(2) nm, c=1.664 4(2) nm, α=82.090(2)°, β=76.001(2)°, γ=86.531(2)°, and V=3.0726(7) nm3, Dc=3.887 g·cm3, Z=2, F(000)=3 196. R1=0.086 7, wR 2=0.185 8. The structure shows that the copper(II) atom is coordinated with two nitrogen atoms from the one phen and three oxgygen atoms from three water, forming a distorted square-pyramid configur...