Lingane

Potassium thiocyanate [333-20-0] M 97.2, m 172°, pK -1.85 (for HSCN), Crystd from H2O if much chloride ion is present in the salt, otherwise from EtOH or MeOH (optionally by addition of Et20). Filtered on a Buchner funnel without paper, and dried in a desiccator at room temperature before being heated for Ih at 150°, with a final 10-20min at 200° to remove the last traces of solvent [Kolthoff and Lingane J Am Chem Soc 57 126 1935]. Stored in the dark. 

In a similar determination described by Lingane and Jones,11 an alloy containing copper, bismuth, lead, and tin is dissolved in hydrochloric acid as described above, and then 100 mL of sodium tartrate solution (0.1 M) is added, followed by sufficient sodium hydroxide solution (5M) to adjust the pH to 5.0. After the addition of hydrazinium chloride (4 g), the solution is warmed to 70 °C and then electrolysed. Copper is deposited at —0.3 volt, and then sequentially, bismuth at —0.4 volt, and lead at —0.6 volt all cathode potentials quoted are vs the S.C.E. After deposition of the lead, the solution is acidified with hydrochloric acid and the tin then deposited at a cathode potential of — 0.65 volt vs the S.C.E. 

The H-type cell devised by Lingane and Laitinen and shown in Fig. 16.9 will be found satisfactory for many purposes a particular feature is the built-in reference electrode. Usually a saturated calomel electrode is employed, but if the presence of chloride ion is harmful a mercury(I) sulphate electrode (Hg/Hg2 S04 in potassium sulphate solution potential ca + 0.40 volts vs S.C.E.) may be used. It is usually designed to contain 10-50 mL of the sample solution in the left-hand compartment, but it can be constructed to accommodate a smaller volume down to 1 -2 mL. To avoid polarisation of the reference electrode the latter should be made of tubing at least 20 mm in diameter, but the dimensions of the solution compartment can be varied over wide limits. The compartments are separated by a cross-member filled with a 4 per cent agar-saturated potassium chloride gel, which is held in position by a medium-porosity sintered Pyrex glass disc (diameter at least 10 mm) placed as near the solution compartment as possible in order to facilitate de-aeration of the test solution. By clamping the cell so that the cross-member is vertical, the molten... 

J J Lingane, Electroanalytical Chemistry, 2nd edn, Interscience, New York, 1958 3.1 M Kolthoff and P J Elving, Treatise on Analytical Chemistry, Part I, Vol 4, Wiley,... 

Lingane and Niedrach have claimed that the h-VI states of tellurium (or selenium) are not reduced at the dropping electrode under any of the conditions of then-investigation however, Norton et al. [42] showed that under a variety of conditions, samples of telluric acid prepared by several different procedures do exhibit well-defined (though irreversible) waves, suitable for the analytical determination of the element. The reduction of Te(H-VI) at the dropping electrode was found coulometri-cally to proceed to the -II state (whereas selenate, Se(-i-VI), was not reduced at the dropping electrode in any of the media reported). 

Lingane, P. J. Hugus, Z. Z. Jr., Normal equations forthe gaussian least-squares refinement of formation constants with simultaneous adjustment of the spectra of the absorbing species, Inorg. Chem. 9, 757-762 (1970). 

Diffusion of electroactive species to the surface of conventional disk (macro-) electrodes is mainly planar. When the electrode diameter is decreased the edge effects of hemi-spherical diffusion become significant. In 1964 Lingane derived the corrective term bearing in mind the edge effects for the Cotrell equation [129, 130], confirmed later on analytically and by numerical calculation [131,132], In the case of ultramicroelectrodes this term becomes dominant, which makes steady-state current proportional to the electrode radius [133-135], Since capacitive and other diffusion-unrelated currents are proportional to the square of electrode radius, the signal-to-noise ratio is increased as the electrode radius is decreased. 

P.J. Lingane, Chronopotentiometry and chronoamperometry with unshielded planar electrodes. Anal. Chem. 36, 1723-1726 (1964). 

Z.G. Soos and P.J. Lingane, Derivation of the chronoamperometric constant for unshielded, circular, planar electrodes. J. Phys. Chem. 68, 3821-3828 (1964). 

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