Polyanion Condensation in Inorganic and Hybrid Fluoridometallates (IV) of Octahedrally Coordinated Ti, Zr, Hf, V, Cr, W, Mn, Ge, Sn, and Pb

Abstract

In fluorides, the M4+ cations of M = Ti, V, Cr, Mn, Ge, Sn, and Pb favour the octahedral coordination of six F ligands. Some examples of M4+ with larger cations (M = Zr, Hf, W) in octahedral coordination are also known. If not enough F ligands are available to have isolated MIVF6 octahedra, they must share their F ligands. The crystal structures of such fluoride metalates (IV) show the variety of possible structural motifs of the zero-dimensional oligomeric anions [M2F11]3− (M = Ti, Cr), [M3F15]3− (M = Zr, Hf), [M3F16]4− (M = Ge), [M4F18]2− (M = Ti, W), [M4F19]3− (M = Ti), [M4F20]4− (M = Ti), [M5F23]3− (M = Ti), [M6F27]3− (M = Ti), [M6F28]4− (M = Ti), [M8F36]4− (M = Ti, Mn), [M10F45]5− (M = Ti) to one-dimensional chains ([MF5]−)∞ (M = V, Ti, Cr, Ge, Sn, Pb), double chains ([M2F9]−)∞ (M = Ti, Mn), columns ([M3F13]−)∞ (M = Ti), ([M4F19]3−)∞ (M = Ti), ([M7F30]2−)∞ (M = Ti), ([M9F38]2−)∞) (M = Ti), two-dimensional layers ([M2F9]−)∞ (M = Cr), ([M8F33]−)∞ (M = Ti), and three-dimensional ([M6F27]3−)∞ (M = Ti) architectures. A discrete monomeric [M2F9]− anion with two MIVF6 octahedra sharing a common face has not yet been experimentally demonstrated, while two examples containing discrete dimeric [M2F10]2− anions (M = Ti) with two MIVF6 octahedra sharing an edge are still in question.