Ammonia molecular conductance

As an example of this, consider the three compounds obtained from hexammino-eobaltie chloride by replacing ammonia by nitrito-groups. The same total number of acidic radicles is retained in the molecule, but the derivatives differ in electrical conductivity in equivalent solutions. The molecular conductivity of hexammino-eobaltie chloride at 25° C. and 1000 litres dilution is 431-6 of the mononitrito-derivative, [Co(NH3)5(N02)]C12, is 246-4 of the di-derivative, [Co(NH3)4(N02)2]C1, is 98-83 and of the trinitrito-derivative, [Co(NH3)3(N02)3], is zero, this being a non-electrolyte. Further substitution transforms the complex from cation to anion thus [Co(NH3).2(N02)4]K. 

In the annnino-platinous compounds there is, as in the other amniino-metallic compounds, a complete transition series from tetrammino-platinous salt to tetra-acido-platinous salt for example, tetrammino-platinous chloride, [Pt(NH3)JC12, chloro-triammino-platinous chloride, [Pt(NH3)3Cl]Cl, dichloro-diammino-platinum, [Pt(NH3)2Cl2], trichloro-ammino-platinous salt, [Pt(NH3)Cl3]K, and potassium chloropiatinite, [PtCl6]K2, where all the ammonia is replaced by chlorine. Comparing the molecular conductivities, the first-mentioned compound has conductivity at 1000 litres dilution of 260, the next 115-8 in the third compound the conductivity drops almost to zero, the fourth has conductivity of 106-8, and the last salt has conductivity of 267.2... 

In their first publication on this subject,59 Werner and Miolati showed that the molecular conductances (fx) of coordination compounds decreased as successive molecules of ammonia were replaced by acid residues (negative groups or anions). For cobalt(III) salts, they found that fi for luteo salts (hexaammines) > fi for purpureo salts (acidopentaammines) > /t for praseo salts (di-acidotetraammines). The conductance fell almost to zero for the triacidotriammine Co(N02)3-(NH3)3 and then rose again for tetracidodiammines, in which the complex behaved as an anion. By such measurements, Werner and Miolati determined the number of ions in complexes of cobalt(III), platinum(II) and platinum(IV). They not only found support for the coordination theory, but they also elucidated the process of dissociation of salts in aqueous solution and followed the progress of aquations. 

PPX films containing PbO nanocrystals also show increase in their conductivity under action of small quantities of ammonia and ethanol vapors from gaseous environment [89, 102, 103]. This effect takes place in the presence of water vapors only and so, most probably, is due to the formation of ionized or highly polarized molecular complexes NH3 H2O and C2H5OH H2O. The responses of conductivity to ammonia and ethanol are also reversible the film conductivity returns to its initial value after the removal of these substances from the surrounding atmosphere. 

MS analysis was conducted on the deactivated catalysts from the MAT reactors using a VG instrument in which the probe was heated from ambient to 500 C at a rate of 20 C min1 and spectra over the mass range 50-600 were recorded every 5s. Spectra were recorded in both electron impact (El) and chemical ionisation (Cl, with ammonia) modes. A number of deactivated samples have also been analysed after extraction in chloroform to remove physically-trapped molecular species. 

The small steric size and propensity of cyanide groups to bridge metal centers have limited their use as ligands in molecular coordination chemistry of the actinides, where they are prone to form amorphous polymeric products. Limited metathesis studies have been conducted. Reaction of tetravalent halides with alkali metal cyanides in liquid ammonia is reported to give rise to a product of the formula UX3(CN)-4NH3, whereas use of the larger thorium ion yields unidentified products. 

The low-molecular-weight fraction of caustic caramel contains roughly 50 components, but the majority of them are present in only minute proportions. Comparative gas - liquid chromatographic studies conducted by Patey and coworkers on caustic and ammonia caramels showed that the low-molecular-weight fraction of caustic caramel is very poor in components of higher retention time. 

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