The synthesis and crystal structure of diaquacobalt tetracyanonickelat
e tetrahydrate are reported. The structure of Co(H2O)(2)Ni(CN)(4).4H(2
)O is composed of alternating metal cyanide sheets add layers of hydro
gen-bonded water molecules. The title compound is isostructural with C
d(H2O)(2)Ni(CN)(4).4H(2)O.