The morpholinebiguanidine (Morph) [HMorph]ClO4 (I) and [M2+(HMorph)Cl-3] [M = Zn (II) and Co (III)] are synthesized and X-ray structurally characterized. Compound I crystallizes in the monoclinic system, space group P2(1)/n, a = 14.169(3), b = 10.875(2), c = 7.914(2) Angstrom, gamma = 78.58(3)degrees, Z = 4, rho(calcd) = 1.510 g/cm(3), R = 0.0666; crystals II are triclinic, space group P (1) over bar, a = 13.303(4), b = 7.653(2), c = 7.787(2) Angstrom, alpha = 112.40(3)degrees, beta = 89.04(3)degrees, gamma = 63.86(3)degrees, Z = 2, rho(calcd) = 1.781 g/cm(3), R = 0.0713. Crystals II and LII are isostructural. The ionic structure of I is built from the [HMorph](+) cations and ClO4- anions. The tetrahedral environment of the Zn(II) atom in molecular compound II incorporates three Cl atoms (average Zn-Cl distance 2.255 Angstrom) and the monodentate HMorph(+) cation coordinated through the central nitrogen atom (Zn-N 2.101 Angstrom). The systems of hydrogen bonds in the crystals are discussed.