Lead ions, glasses

Spot test place a drop of the test solution on a watch glass or on a spot plate, add a drop of ammonium carbonate solution and stir (this renders any mercury(I) or lead ions unreactive by precipitation as the highly insoluble carbonates). Remove one drop of the clear liquid and place it on drop-reaction paper together with a drop of the potassium chromate reagent. A red ring of silver chromate is obtained. 

It prefers pyramidal structure with its lone pair electrons projecting away from the plane of four oxygens. This lone pair, indeed, impedes the motion of alkali ions in alkali lead borate glasses stickiness of the lone pair) (Ganguli et al., 1999) leading to rather low ionic conductivity in spite of the open network structures. 

Continuous dynode multipliers with a channeltron . The ions are directed towards a collector whose entrance, in the form of a horn, is made of a lead doped glass with which acts as the conversion cathode. The ejected electrons are attracted towards a positive electrode (Figure 16.26) and their collisions against the internal walls give rise to multiplication, as with the separated dynodes. The assembly is usually mounted off-axis to avoid the impact of neutral species as well as photons emitted by the filament, equally susceptible to the removal of the electrons. 

Many other systems have subsequently been found to display anion conductivity. The electrical conductivity of lead fluoroborate and fluorogermanate glasses is similar to that of the lead fluorosilicate glasses. Calcium fluoroaluminate glasses also conduct by fluorine migration. Fluorophosphate glasses have also proven to be good anionic conductors. All of these systems are free of alkali ions. 

The incorporation of network modifier lead ions into the vanadate-tellurate glasses enhances the breaking of axial Te-O-Te linkages in the [Te04] trigonal bypiramidal structural units. As a consequence, three-coordination tellurium is formed and accumulated. The band centered at about 750cm-i indicates the presence of the [TeOs] structural units [17,... 

Table 8. Effect of Ar ion bombardment on the atomic structure of the lead-silicate glasses surface layers...

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