No abstract available

[en] This patent describes a catalyst for converting methane in the presence of oxygen into higher hydrocarbon products consisting essentially of (1) a base metal oxide where the metal is selected from the group consisting of metals of (a) Group IIA metals of the Periodic Table excluding Mg, which are Be, Ca, Sr, Ba and mixtures thereof; and (b) Sc, Y, rare earth metals of the Periodic Table excluding Ce, Pr, and Tb, which are La, Nd, Sm, Eu, Gd, Dy, Ho, Er, Tm, Yb, and Lu mixtures thereof; and (2) a promoter oxide present in an amount of up to 50 wt% of the mixture where the metal is selected from the group consisting of (a) Group IA metals of the Periodic Table, which are Li, Na, and K provided that the base metal oxide is not just selected from (1)(a) alone; (b) Group IIA metals of the Periodic Table excluding Mg, which are Be, Ca, Sr, and Ba provided that base metal oxide is not just selected from (1)(a) alone; (c) Sc,Y, and rare earth metals of the Periodic Table excluding Ce, Pr, and Tb, which are La, Nd, Sm, Eu, Gd, dy, Ho, Er, Tm, Yb, and Lu, provided that the base metal oxide is not just selected from (1)(b) alone; and (d) mixtures thereof

[en] An updated bibliography of diffusion data in oxides is provided for the materials scientist who requires a convenient source of published results. The scope of the review has been enlarged to include data for the diffusion of the host and impurity species in both binary and multiple oxides. Brief descriptions of terminology, diffusional behaviour and new measurement techniques are followed by tables of selected results and associated experimental details. (author)

[en] Formation of quaternary oxides CaABB'O₇ of the composition at A=Ti, Zr, Hf, Sn, B=Al, Ga, Cr, Fe, In, B'=Sb, Nb, Ta is studied. Crystal zirconolite structure has been found in twelve samples containing gallium, ferrum (3) titanium, zirconium, hafnium, niobium, tantalum and antimony (5). In the cases, when A=Sn, B=Al quaternary oxides of the above composition are not formed. It is shown that zirconolite structure stability depends not only on cation dimensions but also on their electron structure

[en] Formation enthalpies of complex perovskite-like oxides and their hexagonal analogs of the composition: Ba₂ReFeO₆, Sr₂ReFeO₆, Sr₂ReMnO₆, Ca₂ReMnO₆, Sr₂WCrO₆, Sr₂MoCrO₆, Ca₂MoCrO₆, Ca₂WCrO₆, Ba₃Fe₂ReO₉, Ba₃Cr₂ReO₉, Ba₂RhTaO₆ and B₂ScIrO₆ from simple oxides were calculated by approximate method using enthalpies of the cations coordination change in oxygen medium. The conclusion was made that enthalpy stabilization of the oxide with regard to simple oxides is mainly determined by the change in enthalpies of alkaline earth metal cations

[en] Values for standard enthalpies of formation and dissociation energies for gaseous diatomic monoxides have been selected by critical assessment of experimental data from the literature. Gibbs energy functions, (-(G/sup circle-open//sub T/ -H/sup circle-open/₂₉₈)/T), and enthalpy functions, (H/sup circle-open//sub T/ -H/sup circle-open/₂₉₈), have been calculated from literature values for molecular parameters. Computer methods of storage, processing and retrieval are described and the resulting data are given in tables 4 to 11

[en] This patent describes a composition comprising a mixture of Sr/sub (1+x)/2/La/sub (1-x)/2/Co/sub 1-x/Me/sub x/O/sub 3-δ/ wherein O≤x≤1; δ represents loss of oxygen, and Me is at least one of Fe, Mn, Cr and V; SrMeO/sub 3/, wherein Me is at least one of Ti, Zr and Hf; and at least one Pt group metal

[en] This patent describes an improved process for preparing a superconducting composition. It has the formula MBa₂O_x wherein M is selected from the group consisting of Y, Nd, Sm, Eu, Gd, Dy, Ho, Er, Tm, Yb and Lu; x is from about 6.5 to about 7.0. The composition having a superconducting transition temperature of about 90 K. The process consists essentially of heating a precursor powder in an oxygen-containing atmosphere at a temperature from about 875 degrees C to about 950 degrees C for a time sufficient to form MBa₂Cu₃O_y, where y is from about 6.0 to about 6.4; and maintaining the MBa₂Cu₃O_y in an oxygen-containing atmosphere while cooling for a time sufficient to obtain the desired product. The precursor powder is prepared by forming an aqueous solution of M(NO₃)₃, Ba(NO₃)₂ and Cu(No₃)₂ in an atomic ratio of M:Ba:Cu of about 1:2:3, adding the resulting solution to sufficient oxalic acid to precipitate the metals present as salts, and spray drying the resulting slurry to obtain the precursor powder

[en] The enthalpies of formation of metal oxides, calculated per oxygen atom, show a dependence on two terms, the work function and the electron density differences between the metal and the oxygen. For the transition metals the first term dominates since the second one seems negligibly small. For non-transition metals the electron density term seems to affect greatly the corresponding enthalpy of formation. (author)

No abstract available