Rare earths Rhodium

Growth of rare earth rhodium stannides from excess Sn The crystals can be leached with dilute HC1. As long as the crystals are in contact with the Sn flux, they remain shiny and metallic. Crystals separated from Sn, however, quickly form a black tarnish containing an amorphous mixture of Rh and Sn. The removal of the crystals from the leaching solution as soon as they are free of Sn flux is therefore necessary. 

Maple, B., 1981, Superconductivity and magnetism of rare earth rhodium boride compounds, in Ternary Superconductors, Proc. Intern. Conf. on Ternary Superconductors, Lake Geneva, WI, USA (1980), eds. G.K. Shenoy, B.D. Dunlap and F.Y. Fradin (North-Holland, Amsterdam) pp. 131-139. 

Johnston, D.C. and H.F. Braun, 1982, Systematics of superconductivity in ternary compounds, in Superconductivity in Ternary Compounds, Vol. 2, eds. 0. Fischer and M.B. Maple (Springer, Berlin). Maple, M.B., 1981, Superconductivity and magnetism of rare earth rhodium boride compounds, in Ternary Superconductors, Proc. Intern. Conf. on Ternary Superconductors, Lake Geneva, WI, USA (1980), eds. G.K. Shenoy, B.D. Dunlap and F.Y. Fradin (North-Holland, Amsterdam) pp. 131-139. Shelton, R.N. and D.C. Johnston, 1978, Pressure dependencies of the superconducting and magnetic critical temperatures of ternary rhodium borides, in High Pressure and Low Temperature Physics, eds. C.W. Chu and J.A. Wollam (Plenum, New York) pp. 409-417. 

Johnston, D.C., W.A. Fertig, M.B. Maple and B.T. Matthias, 1978, Solid State Commun. 26, 141. MacKay, H.B., L.D. Woolf, M.B. Maple and D.C. Johnston, 1979, Phys. Rev. Lett. 42, 918. Maekawa, S. and C.Y. Huang, 1980, Roles of crystal field in magnetic superconducting rare earth rhodium borides, in Crystalline Electric Field and Structural Effects in f-electron Systems, eds. J. Crow, R.P. Guertin and T.W. Mihalisin (Plenum, New York) p. 561. 

Maple, M.B., H.C. Hamaker and L.D. Woolf, 1982, Superconductivity, magnetism and their mutual interaction in ternary rare earth rhodium borides and some ternary rare earth transition metal stannides, in Superconductivity in Ternary Compounds n. Topics in Current Physics, Vol. 34 (Springer, Berlin) pp. 99-141. 

Moore, M. D. and Kaplan, S. (1992) Identification of intrinsic high-level resistance to rare-earth oxides and oxyanions in members of the class Proteobacteria Characterization of tellurite, selenite, and rhodium sesquioxide reduction in Rhodobacter sphaeroides. J. Bacteriol. 174,1505-14. 

Pt-Group Metals. Among the six metals (Ru, Rh, Pd, Os, Ir, and Pt) in the platinum group, rhodium (Rh), paradium (Pd), and platinum (Pt) assist the formation of SWNTs (48). Of the three metals, Rh is the most effective for producing SWNTs. Cathode soot produced from Rh contains SWNTs densely, whereas the density in SWNTs is comparable with that for rare-earth metal catalysts such as Y, La, and Ce. 

Complex oxides of the perovskite structure containing rare earths like lanthanum have proved effective for oxidation of CO and hydrocarbons and for the decomposition of nitrogen oxides. These catalysts are cheaper alternatives than noble metals like platinum and rhodium which are used in automotive catalytic converters. The most effective catalysts are systems of the type Lai vSrvM03, where M = cobalt, manganese, iron, chromium, copper. Further, perovskites used as active phases in catalytic converters have to be stabilized on the rare earth containing washcoat layers. This then leads to an increase in rare earth content of a catalytic converter unit by factors up to ten compared to the three way catalyst. 

Within the current TWC catalyst washcoats, rhodium is susceptible to deleterious interactions with various components during a prolonged lean high temperature excursion. To elucidate the potentially detrimental rhodium compounds formed under such circumstances, unsupported rhodium oxides, rare earth metal rhodates, and aluminum rhodate are characterized and measured for catalytic activity. The intrinsic activities at 673K of NO, CO and CjHg conversions over various unsupported rhodium oxides species are basically structure insensitive. However, the intrinsic activities at the same temperature of both the rare earth metal rhodates and aluminum rhodate appear to be sensitive to their structure. The interaction between rhodium and the rare earths especially cerium, is found to be much stronger than that between rhodium and aluminum. 

The present investigation was conducted to identify and determine the degree of Rh-base metal oxide interaction, using unsupported rhodium oxides and bulk aluminum and rare earth metal rhodates. Catalytic activities were determined using monolithic catalysts containing various bulk rhodium species exposed to a simulated stoichiometric auto exhaust composition. The activities were correlated with information obtained from CO chemisorption measurements, temperature-programmed reduction,... 

The elemental contribution to neutron absorption by fission products tends to follow the effective fission yield of the elements, but with exceptions for several individual elements. The rare earths neodymium, promethium, samarium, europium, and gadolinium, as well as xenon and cesium, are the important neutron-absorbing elements resulting from the high-mass fission-yield peak, and rhodium and its near neighbors are the important neutron absorbers from the low-mass peak. 

The trimethylsilylated silicic acids formed in this instance are soluble in conventional organic solvents, and their volatility is sufficiently high for them to be analysed by gas chromatography. Carzo and Hoebbel [411] carried out a comprehensive study of the chromatographic retention of various trimethylsilylated silicic acids on different stationary phases Apiezon L and silicone OV-1 and OV-17. The analysis of metals in the form of volatile complexes continues to attract attention, and have been described for analysing sodium [412], potassium [412], radium [413], caesium [413], barium [414], calcium [414], strontium [415], beryllium [416, 417], magnesium [418], zinc [419, 420], nickel [419], mercury [421], copper [422, 423], silver [424, 425], cadmium [421], indium [426, 427], g ium [428], scandium [217], cobalt [421], thallium [426], hafnium [429, 430], lead [431, 432], titanium [430], vanadium [433], chromium [434-436], manganese [426], iron [437], yttrium [438], platinum [439,440], palladium [439, 441, 442], zirconium [430], molybdenum [443], ruthenium [444], rhodium [445], rare earths [446—449], thorium [221, 450, 451] and uranium [221, 452]. The literature on GC analysis of metal chelates was reviewed by Sokolov [458]. 

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