Caesium compounds

studies have been made at 10 and 310 K of caesium cyanate and of NCO isolated in caesium iodide by employing the alkali-metal halide pressed disc technique. On replacing CsCNO by KCNO, heating for several hours at 673 K was necessary to encourage diffusion away of ions and prevent absorptions due to KCNO appearing with aging.  

The crystal structure of caesium triselenocyanate, Cs(SeCN)3, has been determined as monoclinic, space group C2/c, with a = 7.969, fc = 21.156, c = 5.593 A, 3 = 98.84° and Z = 4. The selenium sequence in the triselenocyanate anion is very nearly linear, with ZSeSeSe= 178.31° and Se—Se bond length 2.650 A, which is 0.31 A longer than single covalent Se—Se bonds. The middle selenocyanate group is exactly linear and, within experimental error, the terminal selenocyanate groups are also linear.  

Inorganic Chemistry of the Main-group Elements 12 Caesium Compounds 

Calorimetric measurements of the enthalpy of reaction of caesium hydrogen acetylide with water have been combined with auxiliary thermochemical data to derive the standard enthalpy of formation AH°9S= 18.84 kcal moT1 for the compound. The compound is probably considerably unstable with respect to its elements.269 

N=0 bond. From these data, the ring formula Cs N=0 is proposed.  

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The structure of Helvite, Mn CBeSiOJjS, has been reported. The tetrahedral manganese ii) ions are bonded to one sulphur and three oxygen atoms. M2Mn3S4 (M = Rb or Cs) have been prepared by reactions in the molten state under nitrogen. An X-ray study on the caesium compound showed the manganese and caesium atoms to be arranged in layers separated by layers of sulphur atoms. ... 

Caesium compounds find application in pyrotechnic formulations to provide a source of near IR radiation for night vision devices which are widely used as electro-optical equipment for surveillance, searching and tracking in the near IR(NIR) region of the electromagnetic spectrum. Lohkamp suggested the use of... 

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. 

Cadmium sulphate [10124-36-4] M 769.5. Crystd from distd water by partial evapn in a desiccator. Caesium compounds see cesium compounds. 

Preparation.—The isolation of caesium compounds is facilitated by the relatively low solubility of certain double salts, such as the alums, chloroplatinates, and double chlorides with antimony, tin, and lead.3 Its separation from rubidium depends on the solubility of its carbonate in alcohol, that of rubidium being only slightly soluble. 

Atomic Weight.—The chemical properties of caesium indicate its close relationship to the other alkali-metals. It is univalent, forming compounds of the type CsX, its atomic weight and hydrogen equivalent being the same. Its atomic weight is of the order Cs =133 a value conformed by the specific-heat method (Vol. I., p. 88) by the isomorphism of the caesium compounds with those of potassium, ammonium, and rubidium (Vol. I., p. 74) by the correspondence of the properties of the metal and its compounds with the periodic system by the formation of a univalent cation and by the depression of the freezing-point of bismuth chloride and mercuric chloride produced by caesium chloride. 

Caesium compounds impart a reddish-violet coloration to the Bunsen flame, similar to that given by rubidium. The chloride forms an insoluble double chloride with stannic chloride of the formula CsgSnCle,1 and also a double salt with antimony chloride.2 Mackenzie and Marshall s method 3 described for rubidium (p. 199) is also applicable to the detection of caesium.4... 

Cs NMR of Crystalline Caesium Compounds Cs NMR of Minerals and Zeolites Cs NMR of Fullerides, Superionic Conductors and Semiconductors La NMR... 

Cs is a spin I = h nucleus of 100% natural abundance and a very small quadrupole moment of — 3.4 X 10 m. Cs in inorganic caesium compounds (Table 10.7) shows a moderate chemical shift range (about 300 ppm). The chemical shifts are normally referenced to aqueous CsCl solution. 

Table 9 Enthalpies of formation of complex caesium compounds...

Hexadienyl-caesium compounds have been generated from 1,4-, 2,4- or 1,5-hexadienes with Cs/18-crown-6 or BuLi/Bu OCs in THE the geometries in solution were deduced from the derivatisation products. ... 

Another means of studying the geometry of vinyl carbanions is by investigation of the reactions of the interesting vinyl-silver and -caesium compounds obtained by addition of the corresponding metal fluorides to per-fluoroalkynes. Further details of the chemistry of these vinyl-metal compounds have appeared in an American Ph.D. thesis. " Caesium fluoride addition to hexafluorobut-2-yne is reversible some of the reactions of the butenylcaesium present in equilibrium with the acetylene are shown in Scheme 54. 

Proton irradiation of solid caesium compounds, to give radio-iodine recoils, indicates that the highest oxidation states of I are found in oxygen-containing salts. The authors suggest that 1 0 is a stable recoil product in the solid state, and is probably the precursor of I Or. 

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