Rubidium graphite

Rubidium graphite and cesium graphite are prepared In similar fashion. 

Whereas technique (4) works for all alkali metals, lithium and sodium behave differently from potassium, rubidium, and cesium with respect to graphite on direct combination. The last three react facilely with graphite, to form compounds CgM (first stage) and Ci2 M (stage n > 1), but lithium reacts only under more extreme conditions of temperature or pressure, or both, to form compounds of formula CenLi (G3,... 

Graphite in contact with liquid potassium, rubidium or caesium at 300°C gives intercalation compounds (CgM) which ignite in air and may react explosively with water [1], Fullerene black —probably a finely divided and distorted graphite — impregnated with potassium explodes spontaneously in air [2],... 

Atomic absorption signal from 60 gaseous rubidium atoms observed by laser wave mixing. A 10-microliter (10 x 10 6 L) sample containing 1 attogiam (1 x 10-18 g) of Rb was injected into a graphite furnace to create the atomic vapor. We will study atomic absorption spectroscopy in Chapter 21. [R K. Mickadelt,... 

Fullerene, black and shiny like graphite, is the subject of active current research because of its interesting electronic properties. When allowed to react with rubidium metal, a superconducting material called rubidium fulleride, Rb3C6o, is formed. (We ll discuss superconductors in more detail in Section 21.6.) Carbon nanotubes are being studied for use as fibers in the structural composites used to make golf clubs, bicycle frames, boats, and airplanes. On a mass basis, nanotubes are up to ten times as strong as steel. 

Nalimova, V. A., S. N. Chepurko, V. V. Avdeev, and K. N. Semenenko. 1991. Intercalation in the graphite-rubidium system under high pressure. Synth. Metals 40 267-273. 

The presence of the potassium atoms causes the distance between the layers of carbon atoms to increase from the value of 235 pm in graphite to 540 pm in C8K. When rubidium and cesium atoms are placed between the layers, the distances between the carbon layers are 561 and 595 pm, respectively. As would be expected for materials that contain atoms of an alkali metal, these materials are extremely reactive in air, and they react explosively with water. A large number of other intercalation compounds have been prepared that have halogens, interhalogens, or metal halides as the included substances. 

The only system which seems to be promising for industrial application is ruthenium promoted with rubidium on graphite as carrier (see Section 3.6.2.3). Further information on structure, activity and reaction mechanism of non-iron catalysts is given in [102], [172]-[175], Specific references vanadium [176], uranium [177], molybdenum [178]-[180], tungsten [181]. 

While potassium, rubidium, and cesium enter the graphite lattice very readily, sodium and lithium are much less reactive towards graphite and do not appear to form the corresponding compounds. Fredenhagen (19, 20) found that sodium reacts with soot but not with graphite. Tammann... 

Riidorff et al. 66, 72, 54) obtained the ammoniates in a pure state by the action of the blue solution of the alkali or alkaline earth metals on graphite. If the metal is in excess a deep blue graphite compound with the structure of stage 1 results. The strontium and barium compounds are violet at low temperatures. After washing with liquid ammonia and removal of the absorbed ammonia in a vacuum at 0°, the composition corresponds approximately to the formula CiaMeCNHsla- The potassium, rubidium, and cesium compounds may also be obtained by treating CgMe with liquid ammonia. 

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