T:Toxic;13765-24-7Relevant articles and documents
Greis, O.
, p. 227 - 232 (1978)
Activation of O2 over SrF2- and BaF2-promoted SmOF catalysts for the oxidative dehydrogenation of ethane
Au, Chak-Tong,Zhou, Xiaoping
, p. 485 - 491 (1997)
Promotion of rhombohedral SmOF by SrF2 or BaF2 led to significant gain in ethane conversion but little change in ethene selectivity in the oxidative dehydrogenation of ethane. At 893 K, C2H6 conversion and C2H4 selectivity over SmOF were, respectively, 38.8 and 71.2%. With 10% SrF2/SmOF and 20% BaF2/SmOF catalysts, C2H6 conversion became 69.7 and 68.4%, respectively, while C2H4 selectivity was 67.7%. X-Ray diffraction (XRD) studies revealed a small amount of cubic SrF2 but no crystal phase of BaF2 in the promoted catalysts. The SrF2 lattice contracted slightly and the SmOF lattices expanded slightly. We believe that such deformities resulted from ionic exchange/substitution occurring between/within the SrF2 and SmOF phases with creation of active centres. The Raman and O2 temperature programmed desorption (TPD) results, indicated that, above 973 K, dioxygen species on SmOF were converted completely to mono-oxygen species. With the promoted catalysts, such conversion was complete at around 573 K. Because Sm3+ is paramagnetic and owing to the effect of spin-spin interaction, we could not obtain any EPR signals of O2- or O- over SmOF. Over the promoted catalysts, however, EPR signals corresponding to O2- and O- located in the proximity of non-paramagnetic Sr2+ and Ba2+ ions were observed. The conversion of O2- to O- was confirmed and monitored by EPR spectroscopy. We conclude that the deformities generated in the promoted catalysts have facilitated the conversion of dioxygen species to O- species at lower temperature, resulting in better catalytic performance.
The new carbodiimide Li2Gd2Sr(CN2) 5 having a crystal structure related to that of Gd 2(CN2)3
Unverfehrt, Leonid,Stroebele, Markus,Meyer, H.-Juergen
, p. 84 - 88 (2013/03/28)
The new carbodiimide compounds Li2RE2Sr(CN 2)5 (RE = Sm, Gd, Eu, Tb) were prepared by a straight forward solid state metathesis reaction of REF3, SrF2, and Li2(CN2) at around 600 °C. The crystal structure of Li2Gd2Sr(CN2)5 was solved based on X-ray single-crystal diffraction data. Corresponding Li2RE 2Sr(CN2)5 compounds were analyzed by isotypic indexing of their powder patterns. The crystal structure of Li 2Gd2Sr(CN2)5 can be well related to that of Gd2(CN2)3, because both structures are based on layered structures composed of close packed layers of [N=C=N] 2- sticks, alternating with layers of metal ions. The crystal structure of Li2Gd2Sr(CN2)5 can be considered to contain an ABC layer sequence of [N = C=N]2- layers with the interlayer voids being occupied by (three) distinct types of cations. Copyright
Synthesis and optical properties of non-stoichiometric lanthanide (Sm, Eu, Tm, Yb) fluorides
Ivanenko,Kompanichenko,Omelchuk,Zinchenko,Timukhin
, p. 841 - 847 (2010/09/17)
Nonstoichiometric samarium, europium, ytterbium, and thulium fluorides were prepared by reduction of the corresponding trifluorides with the same lanthanide metal or silicon. Crystal lattice type and lattice parameters of the compounds were determined by
The versatility of solid-state metathesis reactions: From rare earth fluorides to carboiimides
Unverfehrt, Leonid,Glaser, Jochen,Stroebele, Markus,Tragl, Sonja,Gibson, Katharina,Meyer, H.-Juergen
, p. 479 - 483 (2009/06/17)
The new carbodiimide compounds LaF(CN2) and LiPr 2F3(CN2)2 were obtained as crystalline powders by solid-state metathesis reactions from 1:1 molar ratios of REF3 (RE = rare earth) and Lisu
