Rubidium metal reactions with

Metals react with nonmetals. These reactions are oxidation-reduction reactions. (See Chapters 4 and 18). Oxidation of the metal occurs in conjunction with reduction of the nonmetal. In most cases, only simple compounds will form. For example, oxygen, 02, reacts with nearly all metals to form oxides (compounds containing O2-). Exceptions are the reaction with sodium where sodium peroxide, Na202, forms and the reaction with potassium, rubidium, and cesium where the superoxides, K02, Rb02, and Cs02 form. 

Preparation. It is made by the reaction of metallic sodium with hot molten rubidium chloride. 

Cesium reacts with water in ways similar to potassium and rubidium metals. In addition to hydrogen, it forms what is known as superoxides, which are identified with the general formula CsO When these superoxides react with carbon dioxide, they release oxygen gas, which makes this reaction useful for self-contained breathing devices used by firemen and others exposed to toxic environments. 

The tetrafluorocobaltates of the alkali metals show12 considerable differences in their reactions with benzene. Lithium tetrafluorocobaltate(III) at 100-130 C gives 3,3,6,6-tetra-fluorocyclohexa-1,4-diene (13) of over 90% purity. This compound has long been postulated1,549 as a major intermediate in the fluorination with cobalt(III) fluoride. The sodium, potassium, and rubidium salts give similar product mixtures (ca. 8 compounds), most being polyfluoroenes (e.g. 14, 8% 15, 12% 16, 35%). 

Less attention has been paid to the reaction of cellulose with rubidium hydroxide and with cesium hydroxide. Heuser and Bartunek101 isolated adducts of rubidium hydroxide and of cesium hydroxide that had the general formula MOH 3 C Hi0Ot. Their studies showed that the concentration, in weight percent, of alkali metal hydroxide required for forming a stable adduct of the lowest alkali content increases with increase in the atomic weight of the metal Li < Na < K < Rb < Cs. However, on a molar basis, this relationship does not hold. No simple relationship exists between the size of cation and the concentration of hydroxide necessary for the formation of a stable adduct. 

The trapped electrons were formed simply by depositing alkali metal atoms on ice or solid alcohols at 77°K. Studies were made of the reactions between sodium or potassium atoms and ice (HgO or D2O), methanol, ethanol, isopropyl alcohol, t-butyl alcohol or dodecanol. The reactions of caesium, rubidium and lithium with ice were also investigated. The deposits were highly coloured and the optical and e.s.r. spectra showed that the electron was no longer associated with the alkali metal ion but had been transferred completely to the solid matrix. 

SAFETY PROFILE A highly corrosive irritant to the eyes, skin, and mucous membranes. Mildly toxic by inhalation, Explosive reaction with alcohols + hydrogen cyanide, potassium permanganate, sodium (with aqueous HCl), tetraselenium tetranitride. Ignition on contact with aluminum-titanium alloys (with HCl vapor), fluorine, hexa-lithium disilicide, metal acetylides or carbides (e.g., cesium acetylide, rubidium ace-tylide). Violent reaction with 1,1-difluoro-ethylene. Vigorous reaction with aluminum, chlorine + dinitroanilines (evolves gas). Potentially dangerous reaction with sulfuric acid releases HCl gas. Adsorption of the acid onto silicon dioxide is exothermic. See also HYDROGEN CHLORIDE (AEROSOL) and HYDROCHLORIC ACID. 

The high reactivities of the alkali metals are illustrated by their vigorous reactions with water. Lithium reacts readily sodium reacts so vigorously that the hydrogen gas it forms may ignite and potassium, rubidium, and cesium cause the H2 to burst into flames when... 

The alkali earth metals form Group 1 of the periodic table, made up of lithium, sodium, potassium, rubidium, cesium, and francium (not shown in Fig. 1.3). Their name derives from the observation that their addition to water generates an alkaline solution. They are all low density, soft, and extremely reactive metals, which are rarely found in their metallic form. This group has properties which are closer and more alike than any other group of the periodic table. Since they desperately want to lose their solitary outer sphere electron, their reactions with almost any other species (including molecular oxygen) are violent and explosive. 

The alkali metals—lithium, sodium, potassium, rubidium, cesium, and francium—make up Group 1 of the periodic table. These metals are highly reactive. For example, if potassium is dropped into water, the reaction will transform potassium into potassium hydroxide and hydrogen gas. When these metals react with water, hydrogen gas is given off, and heat—often hot enough to create flames—can appear. The heat produced by the interaction is enough to liquefy the metal. 

Answer (a) Since rubidium is an alkali metal, we would expect Rb20 to be a basic oxide. This is indeed true, as shown by rubidium oxide s reaction with water to form rubidium hydroxide ... 

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