Structural and infrared and electronic spectroscopic studies of the coordination polymers corresponding to the compounds of simplest formulas M3II[Mn(CN)5NO]2·nH2O (M=Mn, Co, Ni, Cu, Zn, and n=8–16) are reported and discussed in comparison with the corresponding nitroprussides. These polymers have a typical face centered cubic unit cell containing 1 1/3 formula units, except for M=Mn where the crystal system is orthorhombic.