Caesium compounds with oxygen

That the metals of highest atomic number should form compounds with the larger numbers of sulphur atoms is in accordance with their behaviour towards oxygen, where the superoxidcs of rubidium and caesium are the most stable. The polysulphides consist of zig-zag chains of sulphur atoms with the metal atoms situated terminally. 

A quite new type of antibiotic and one of the few naturally-occurring boron compounds is boromycin (86). Hydrolytic cleavage of D-valine with the M(7) hydroxides gave caesium and rubidium salts of this antibiotic, and crystal structure analysis established the formula as (XIIT). The rubidium ion is irregularly coordinated by eight oxygen atoms. Experiments with models showed that the cation site would be the natural place for the—NH3+ end of the D-valine residue, and the whole structure raises the possibility that transport of larger alkali metals is related to the N-ends of peptides and proteins. 

For XV) complexes have been obtained with molecular ratios 1 1 for potassium and sodium salts, 2 3 for rubidium and ammonium thiocyanate, and 1 2 for caesium thiocyanate. The rubidium and ammonium thiocyanate compounds are isomorphous, and the structure of the former was the first of this type to be determined 92). In the crystal there is a 1 1 complex and a molecule of crystallisation of un-complexed (XT). The metal is coordinated by six coplanar oxygen atoms... 

Andrews and co-workers have used the matrix reaction between lithium atoms and some inorganic compounds to produce species of spectroscopic interest. Reaction of lithium with molecular oxygen [301] produces, in addition to the molecule Li02, the molecule LiO and a dimer Li2 02. Reaction with nitric oxide produced a nitroxide compound [302], but analysis of the infrared spectrum indicated that in this compound the lithium atom was bound to the oxygen atom (LiON), rather than to the nitrogen atom (LiNO), as would be expected by analogy with the known compounds HNO and RNO. The matrix deposition of lithium and nitrous oxide [303] leads to the formation of LiO and LijO. The other alkali metals have also been reacted in the same way with nitrous oxide [304]. Potassium, rubidium and caesium all led to the formation of the compounds MO and M2O. No sodium oxides were produced when sodium and nitrous oxide were co-deposited. This is to be compared with the mechanism advanced for the sodium-catalysed gas-phase reaction between N2O and CO, where sodium is assumed to react with N2O, (Section 4, ref. 

As shown in Table II, calixcrown compounds containing six oxygen atoms in the ring(s) are much more selective than classical crown ethers. The complexes best formed with the least hydrated alkali cations (caesium) are probably stabilized by the 7r-bonding interactions arising from the phenyl rings of the 1,3-alternate phenolic units of the calixcrown compounds [22]. 

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