Rubidium silver iodide is a ternaryinorganic compound with the formula RbAg4I5. Its conductivity involves the movement of silverions within the crystal lattice. It was discovered by Dr. Boone Owens while searching for chemicals which had the ionic conductivity properties of alpha-phase silver iodide at temperatures below 146 °C for AgI.[1]
RbAg4I5 can be formed by melting together[2] or grinding together[3] stoichiometric quantities of rubidium iodide and silver(I) iodide. The reported conductivity is 25 siemens per metre (that is a 1×1×10 mm bar would have a resistance of 400 ohms along the long axis).
The crystal structure is composed of sets of iodine tetrahedra; they share faces through which the silver ions diffuse.[4]
RbAg4I5 was proposed around 1970 as a solid electrolyte for batteries, and has been used in conjunction with electrodes of silver and of RbI3.[1] Its conductivity does not exhibit substantial variation with changes in relative humidity.[5]
Rubidium silver iodide family is a group of compounds and solid solutions that are isostructural with the RbAg4I5 alpha modification. Examples of such advanced superionic conductors with mobile Ag+ and Cu+cations include KAg4I5, NH4Ag4I5, K1−xCsxAg4I5, Rb1−xCsxAg4I5, CsAg4Br1−xI2+x, CsAg4ClBr2I2, CsAg4Cl3I2, RbCu4Cl3I2 and KCu4I5.[6][7][8][9]
^Popov, A. S.; Kostandinov, I. Z.; Mateev, M. D.; Alexandrov, A. P.; Regel, Liia L.; Kostandinov; Mateev; Alexandrov; Regel (1990). "Phase analysis of RbAg4I5 crystals grown in microgravity". Microgravity Science and Technology. 3: 41–43. Bibcode:1990MicST...3...41P.{{cite journal}}: CS1 maint: multiple names: authors list (link)
^Hull S. Keen D.A.; Sivia D.S.; Berastegui P. (2002). "Crystal Structures and Ionic Conductivities of Ternary Derivatives of the Silver and Copper Monohalides – I. Superionic Phases of Stoichiometry MAg4I5: RbAg4I5, KAg4I5, and KCu4I5". Journal of Solid State Chemistry. 165 (2): 363–371. Bibcode:2002JSSCh.165..363H. doi:10.1006/jssc.2002.9552.
^Despotuli A.L.; Zagorodnev V.N.; Lichkova N.V.; Minenkova N.A. (1989). "New high conductive CsAg4Br1−xI2+x (0.25 < x < 1) solid electrolytes". Sov. Phys. Solid State. 31: 242–244.
^Lichkova N.V.; Despotuli A.L.; Zagorodnev V.N.; Minenkova N.A.; Shahlevich K.V. (1989). "Ionic conductivity of solid electrolytes in the two- and three-components AgX–CsX (X = Cl, Br, I) glass-forming systems". Sov. Electrochem. 25: 1636–1640.