Compounds rubidium

Rubidium dihydrogen orthophosphate, RbH2P04, has been studied by calorimetry. The enthalpies, AHt and AH2, of the reactions  

The reactions of rubidium and caesium sulphates with barium halides in the solid state and under anhydrous conditions have been studied. With BaCl2, BaBr2, or Bal2, reaction proceeds in two stages in the absence of air to produce BaS04 and the alkali-metal halide at 828—963 K. Conductivity and thermal measurements showed that the exothermic first stage involved formation of a ternary eutectic, whereas the second stage was endothermic. A combination of 

Zviedra and A. levins, LmIv. PSR Ainat. Akad. Vestis. Khim. Ser., 1974, 395. 

thermal, spectroscopic, and chemical techniques have been employed in investigating the thermal behaviour of rubidium selenite up to 1273 K. At 453 K some small decomposition to selenium occurs oxidation in air begins at 583 K producing Rb2Se03,3Rb Se04. This melts at 1263 K without decomposition.  

Rubidium and caesium gallohydrides, RbGaH4 and CsGaH, can be prepared from the elements at 150—220 °C in the absence of solvents in a sealed vessel. Attempts to prepare the corresponding sodium and potassium compounds in a similar fashion were unsuccessful.  

Rubidium trihydrogen selenite RbH3(Se03)2 is orthorhombic with a = 5.9192, b = 17.9506, and c = 6.2519 A, space group The structure 

Pevergne, P. Legrand, and J. Heubel, Bull. Soc. chim. France, 1972, 4106. 

Zakharkin, V. V. Gavrilenko, and Yu. Karaksin, Synth. Inorg. Metal-Org. Chem., 

Tellgren, D. Ahmad, and R. Liminga, J. Solid State Chem., 1973, 6, 250. 

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See Cesium AND CESIUM compounds Liphium and liphium compounds Popassium Rubidium and rubidium compounds Sodium compounds. 

Rubidium metal is commeicially available in essentially two grades, 99 + % and 99.9 + %. The main impurities ate other alkali metals. Rubidium compounds are available in a variety of grades from 99% to 99.99 + %. Manufacturers and suppliers of mbidium metal and mbidium compounds usually supply a complete certificate of analysis upon request. Analyses of metal impurities in mbidium compounds are determined by atomic absorption or inductive coupled plasma spectroscopy (icp). Other metallic impurities, such as sodium and potassium, are determined by atomic absorption or emission spectrograph. For analysis, mbidium metal is converted to a compound such as mbidium chloride. 

Table 3. Toxicity Data for Select Rubidium Compounds ...

Rubidium-87 emits beta-particles and decomposes to strontium. The age of some rocks and minerals can be measured by the determination of the ratio of the mbidium isotope to the strontium isotope (see Radioisotopes). The technique has also been studied in dating human artifacts. Rubidium has also been used in photoelectric cells. Rubidium compounds act as catalysts in some organic reactions, although the use is mainly restricted to that of a cocatalyst. 

The trimolybdates in the solid state are polymeric in nature (119, 120). Two different structure types are obtained as the potassium and rubidium salts K2[Mo3Oi0] and Rb2[Mo3Oi0] H20 shown in Fig. 14. The rubidium compound consists of a chain of Mo06 octahedra, whereas the potassium compound comprises edge-shared distorted Mo05 poly-hedra and Mo06 octahedra (121). 

Johnson GT, Lewis TR, Wagner WD Acute toxicity of cesium and rubidium compounds. Toxicol Appl Pharmacol 32 239-245, 1975... 

The powder diagrams of the ternary mangan(III)-fluorides LiMnF4 [163) KMnF4 and RbMnF4 [166) could not be indexed yet. Possibly the Jahn-Teller distortion not only affects the MnFe --octahedra, but also the symmetry of the unit cells, which, at least in the case of the potassium-and rubidium-compounds, should be very similar to each other. 

Rubidium metal alloys with the other alkali metals, the alkaline-earth metals, antimony, bismuth, gold, and mercury. Rubidium forms double halide salts with antimony, bismuth, cadmium, cobalt, copper, iron, lead, manganese, mercury, nickel, thorium, and zinc. These complexes are generally water insoluble and not hygroscopic. The soluble rubidium compounds are acetate, bromide, carbonate, chloride, chromate, fluoride, formate, hydroxide, iodide,... 

Pure rubidium metal is obtained by reducing pollucite or lepidolite ore using an active metal, followed by vacuum distillation (17). Another method is to reduce pure rubidium compounds thermochemically according to the following reactions (18) ... 

For shipping purposes, the ampul is placed in aluminum foil or polyethylene bags. The wrapped ampul is packed in a metal can and surrounded by an inert filler material such as vermiculite. These precautions are necessary in order to minimize the chances of ampul breakage during shipment. Most rubidium compounds, however, can be shipped as nonhazardous materials. These compounds are usually stored in glass or polyethylene bottles. 

The supply and demand for rubidium compounds has grown steadily since the 1970s. In 1979 the U.S. demand was ca 1040 kg of contained rubidium (16), and total world demand was estimated at approximately twice that of the United States. Reserves of rubidium in North America are estimated at 2 x 103 kg the United States is 100% import-reliant for rubidium, and Canada is the principal source of the raw material (16). The demand for rubidium metal is small compared to the demand for rubidium compounds. Table 2 lists approximate prices of rubidium metal and rubidium compounds. Primary producers of rubidium are Cabot Performance Chemicals (Boyerstown, Pennsylvania), MSA Research Corporation (Callery, Pennsylvania), and CM Chemical Products, Inc. (Berkeley Heights, New Jersey). Research quantities of rubidium in standard and specialized ampuls are available from Strem Chemicals, Inc. (Newburyport, Massachusetts). 

Rubidium acid salts are usually prepared from rubidium carbonate or hydroxide and the appropriate acid in aqueous solution, followed by precipitation of the crystals or evaporation to dryness. Rubidium sulfate is also prepared by the addition of a hot solution of barium hydroxide to a boiling solution of rubidium alum until all the aluminum is precipitated. The pH of the solution is 7.6 when the reaction is complete. Aluminum hydroxide and barium sulfate are removed by filtration, and rubidium sulfate is obtained by concentration and crystallization from the filtrate. Rubidium aluminum sulfate dodecahydrate [7488-54-2] (alum), RbA SO 12H20, is formed by sulfuric acid leaching of lepidolite ore. Rubidium alum is more soluble than cesium alum and less soluble than the other alkali alums. Fractional crystallization of Rb alum removes K, Na, and Li values, but concentrates the cesium value. Rubidium hydroxide, RbOH, is prepared by the reaction of rubidium sulfate and barium hydroxide in solution. The insoluble barium sulfate is removed by filtration. The solution of rubidium hydroxide can be evaporated partially in pure nickel or silver containers. Rubidium hydroxide is usually supplied as a 50% aqueous solution. Rubidium carbonate, Rb2C03, is readily formed by bubbling carbon dioxide through a solution of rubidium hydroxide, followed by evaporation to dryness in a fluorocarbon container. Other rubidium compounds can be formed in the laboratory by means of anion-exchange techniques. Table 4 lists some properties of common rubidium compounds. 

F. Ephraim found that if T denotes the absolute temp, at which the vap. press, of the liberated halogen is equal to one atm., then for corresponding pairs of the caesium and rubidium polyhalides, 5Tc>,/2,i =l 12 and, if v denotes the at. vol., T td is the same for the two members of each series. Given the dissociation temp, of the caesium compound, it is possible to predict the stability of the analogous rubidium compound. F. Ephraim extended the rule to the potassium compounds when the corresponding rubidium compounds are known. 

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