Crystal structures of aninoguanidinium(1+) and aminoguanidinium(2+) hexafluorozirconates

X-ray diffraction study was made on (CN4H7)2xZrF6(1) crystals, referred to monoclinic syngony: a=6.372(1), b=14.586(3), c=6.324(1), γ=99.65(2) deg, Z=2, sp.gr. P21/b, and on (CH4H8)ZrF6(2) crystals, referred to rhombic syngony: a=10.089(2), b=18.349(3), c=7.560(1) A, Z=8, sp.gr. Pba2. Structure 1 is composed of isolated octahedral complex [ZrF6]2- anions and CN4 H7+ cations, which form relatively weak hydrogen bonds N-H...F (2.939 A) with F atoms of anions. Zr-F distances in slightly distorted [ZrF6]2-octahedron - 1.997-2.005 A, values of FZrF angles are approximately equal to 90 deg. The structure 2 is formed by isolated chains of rib-bound Zr-polyhedrons (ZrF8) and CN4H82+ cations, connecting chains by N-H...F hydrogen bonds (2.557-2.975 A). Zr polyhedrons have the configuration of slightly distorted dodecahedron. Lengths of Zr-F bonds in polyhedron are within the range of 1.971-2.277 A