Solvothermal indium fluoride chemistry: Syntheses and crystal structures of K5In3F14, β-(NH4)3InF6 and [NH4]3[C6H21N4]2[In4F21]

The solvothermal syntheses and crystal structures of three indium fluorides are presented. K₅In₃F₁₄ (1) and β-(NH₄)₃InF₆ (2) are variants on known inorganic structure types chiolite and cryolite, respectively, with the latter exhibiting a complex and apparently novel structural distortion. [NH₄]₃[C₆H₂₁N₄]₂[In₄F₂₁] (3) represents a new hybrid composition displaying a unique trimeric metal fluoride building unit.     

The synthesis and crystal structures of the first rare-earth alkaline-earth selenite chlorides MNd10(SeO3)12Cl8 (M=Ca and Sr)

Two new alkaline-earth Nd selenite chlorides MNd₁₀(SeO₃)₁₂Cl₈ (M=Ca, Sr) were obtained using crystal growth from alkaline-earth chloride melts in quartz tubes. These new compounds crystallize in the orthorhombic system in space group C cca (#68). The compounds were studied by energy dispersive X-ray spectroscopy (EDX) and X-ray diffraction. It was shown that both compounds adopt the same structure type, constructed by complex [M₁₁(SeO₃)₁₂]⁸⁺ slabs separated by chloride anion layers perpendicular to the longest cell parameter. The SeO₃ groups show a pyramidal shape and may be described as SeO₃E tetrahedra. Such SeO₃ groups decorate the Nd-O skeletons forming the [M₁₁(SeO₃)₁₂]⁸⁺ slabs.     

New linear chain compounds based on an aza macrocyclic copper(II) complex with halide ions

We have shown by X-ray diffraction analysis that participation of functional groups on the macrocycle in formation of hydrogen bonds promotes formation of crystal lattices with previously undescribed linear polymer chains ... Cu ... Hal ... Cu ... Hal ... We have used spectral methods to confirm the presence of a Cu-Hal interaction, which makes these compounds promising for design of new materials with anisotropic physical properties. Deceased Translated from Teoreticheskaya i éksperimental'naya Khimiya, Vol. 34, No. 6, pp. 355–359, November–December 1998.     

Hydrothermal chemistry of oligomeric vanadium oxyfluorides

Nine new vanadium oxyfluorides, containing ten different oligomeric vanadium (oxy)fluoride anions have been prepared by solvothermal synthesis in water-ethylene glycol and using organic cations as co-crystallising agents. Crystal structures are reported for each. Amongst the ten structure types, five represent previously unobserved moieties, including one monomeric unit (cis-[VOF4(H2O)]2-), two dimers ([V2O2F6(H2O)2]2- and [V2O2F8]4-) and two tetramers (both isomers of composition [V4O4F14]6-). Structural relationships between the various units are discussed, together with some rationalisation of their occurrence as a function of synthetic variables.     

Conservative methods for the Toda lattice equations

We are concerned with the numerical integration of the Todalattice equations by using different conservative methods. Numericalexperiments suggest that the global error for isospectral schemesdecreases exponentially with time but it is almost constantfor either symplectic or more general integrators. We providea theoretical explanation for these experimental findings.