Silver rubidium iodide

In purely ionic compounds, the conductivity from these mechanisms is intrinsic and relates only to the entropy-driven Boltzmann distribution the conductivity will thus increase with increase in temperature. Because the number of defects is quite limited, the conductivities are low, of the order of I0-6 ft 1 cm-1. In addition, extrinsic vacancies will be induced by ions of different charge (see page 264). There exist, however, a few ionic compounds that as solids have conductivities several orders of magnitude higher. One of the first to be studied and the one with the highest room-temperature conductivity, 0.27 fl-1 cm-1, is rubidium silver iodide, RbAg j.1 1... 

The conductivity may be compared with that of a 35% aqueous solution of sulfuric acid. 0.8 fl-1 cm-1. The structure consists of a complex (not a simple closest-packed) arrangement of iodide ions with Rb ions in octahedral holes and Ag+ ions in tetrahedral holes. Of the 56 tetrahedral sites available to the Ag+ ions, only 16 are occupied, leaving many vacancies. The relatively small size of the silver ion (114 pm) compared with the rubidium (166 pm) and iodide (206 pm) ions give the silver ion more mobility in the relatively rigid latice of the latter ions. Furthermore, the vacant sites are arranged in channels, down which the Ag+ can readily move (Fig. 7.16). 

Fig. 7.16 Structure of RbAgjIj crystal. Iodide ions are represented by large spheres, rubidium ions by small white spheres. Tetrahedral sites suitable for silver ions are marked with short sleeves on horizontal arms. (The easiest to see is perhaps the one formed by the triangle of iodide ions front left with the fourth iodide ion behind and to the right.)...

QUECKSILBER (German) (7439-97-6) Violent reaction with alkali metals, aluminum, acetylenic compounds, azides, boron phosphodi iodide (vapor explodes), bromine, 3-bromo-propyne, chlorine, chlorine dioxide, ethylene oxide, lithium, metals, methyl silane (when shaken in air), nitromethane, peroxyformic acid, potassium, propargyl hromide, rubidium, sodium, sodium carbide. Forms sensitive explosive products with acetylene, ammonia (anhydrous), chlorine, picric acid. Increases the explosive sensitivity of methyl azide. Mixtures with hot sulfuric acid can be explosive. Incompatible with calcium, sodium acetylide, nitric acid. Reacts with copper, silver, and many other metals (except iron), forming amalgams. 

Cesium fluoride Rubidium iodide Silver chloride... 

A. Metcalfe [1977] The Anodic Dissolution of Silver into Silver Rubidium Iodide-Impedance Measurements, J. Electroanal. Chem. 88, 187-192. 

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