CS-metal

C07-0131. A hydrogen atom undergoes an electronic transition from the = 4 to the = 2 state. In the process the H atom emits a photon, which then strikes a cesium metal surface and ejects an electron. It takes 3.23 X 10 J to remove an electron from Cs metal. Calculate (a) the energy of the — 4 state of the H atom (b) the wavelength of the emitted photon (c) the energy of the ejected electron and (d) the wavelength of the ejected electron. 

However, using alkaline earth metal fluorides gives a less pronounced improvement. The use of CsF and LiF as CIM layer has the same effect. However, unlike LiF, CsF reacts directly with A1 and releases Cs metal, whereas the dissociation of LiF in the presence of A1 is thermodynamically disallowed and proceeds only in the presence of suitable reducible organic materials such as Alq3. Thus CsF is more generally applicable to many organic materials. 

Main uses. Caesium metal is used in the production of vacuum tubes as a scavenger to reduce residual gaseous impurities after the tubes have been sealed. Cs may be generated in situ by heating a pellet of caesium chromate mixed with a metal powder (Zr, Ca, Ba). Cs metal is used as the propellant in ion thrusters (employed in satellites for orientation control) it is ionized in a vacuum chamber, the Cs+ are then accelerated through a nozzle (high specific impulse because of high atomic mass). 

Fig. 18. Potential curves for the forming of a surface Cs+02- layer on Cs-metal.

If the vapor of Cs-metal is brought into contact with layers of tetracyano-pyrene, a deep violet complex is formed 29-3°). At 77 °K O/P conversion occurs over this complex, but no H/D exchange. Between 190 and 373 °K O/P conversion and H/D exchange occur at comparable rates and with the same activation energy (3.7 Kcal/mole). Neither reaction is catalyzed by Cs-metal or tetracyanopyrene alone. In more extended work of the same nature it was found 31-34) two mechanisms of exchange can be distinguished ... 

One might imagine many fascinating applications for supracyclopenta-dienyl metal systems with functional groups. However, this will most likely require a spacer unit to prevent charge transfer between the C5 and functional moiety, if the Cs-metal coordination is to be preserved. Such systems exist or have recently been developed, for example, in connection with the search for a liquid crystalline organometallic complex (see Section IV,A,2,b). 

In regard to the uiUc ketones, they form the acetates m their enol form equally well io acid medium, the /3-diketones and the /7-keto esters, in the presence cS metals or bases, give compovindR with an acetyl group on the carbon atom of the active methylene group ... 

Information about physicochemical and complexation properties of polyvinylsulfonic acid (PVSH) or, more correctly, polyethylenesulfonic acid (PESH) [11] is much less available than that of the polyamines. PVSH (or PESH) is a simple, strong polyacid (see Fig. 6.6), so that partial ionization and possible hydrolysis effects, encountered with weak polyacids and their salts (e.g., polyacryfic acid and its salts), do not complicate the picture [76]. Commercially available sodium salt, PVSNa, is a brittle hygroscopic solid, soluble in water, but insoluble in organic solvents (methanol, dioxane, etc.) [77]. Viscosity behavior of the alkali metal salts was studied by several groups [28, 52, 75-77], but data are too scattered to be trustworthy. The PVS polyanion shows a definite selectivity in ion binding with alkali Li, Cs metals in the presence of Na, K hah des [78]. 

Brooks CS, Metal Recovery From Industrial Waste, Lewis... 

---