Rubidium silver iodide is a ternary

inorganic compound In chemistry, an inorganic compound is typically a chemical compound that lacks carbon–hydrogen bonds, that is, a compound that is not an organic compound. The study of inorganic compounds is a subfield of chemistry known as '' inorganic chemis ...

with the formula RbAg₄I₅. Its conductivity involves the movement of

silver Silver is a chemical element with the symbol Ag (from the Latin ', derived from the Proto-Indo-European ''h₂erǵ'': "shiny" or "white") and atomic number 47. A soft, white, lustrous transition metal, it exhibits the highest electrical ...

ions within the crystal lattice. It was discovered while searching for chemicals which had the ionic conductivity properties of alpha-phase

silver iodide Silver iodide is an inorganic compound with the formula Ag I. The compound is a bright yellow solid, but samples almost always contain impurities of metallic silver that give a gray coloration. The silver contamination arises because AgI is hi ...

at temperatures below 146 °C for AgI. RbAg₄I₅ can be formed by melting together or grinding together stoichiometric quantities of rubidium iodide and

silver(I) iodide Silver iodide is an inorganic compound with the formula Ag I. The compound is a bright yellow solid, but samples almost always contain impurities of metallic silver that give a gray coloration. The silver contamination arises because AgI is hig ...

. The reported conductivity is 25

siemens Siemens AG ( ) is a German multinational conglomerate corporation and the largest industrial manufacturing company in Europe headquartered in Munich with branch offices abroad. The principal divisions of the corporation are ''Industry'', ''E ...

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 In geometry, a tetrahedron (plural: tetrahedra or tetrahedrons), also known as a triangular pyramid, is a polyhedron composed of four triangular faces, six straight edges, and four vertex corners. The tetrahedron is the simplest of all th ...

; they share faces through which the silver ions diffuse. RbAg₄I₅ was proposed around 1970 as a solid electrolyte for batteries, and has been used in conjunction with electrodes of silver and of RbI₃. Its conductivity does not exhibit substantial variation with changes in

relative humidity Humidity is the concentration of water vapor present in the air. Water vapor, the gaseous state of water, is generally invisible to the human eye. Humidity indicates the likelihood for precipitation, dew, or fog to be present. Humidity dep ...

. 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 An advanced superionic conductor (AdSIC) in materials science, is fast ion conductor that has a crystal structure close to optimal for fast ion transport (FIT). History The term was introduced in a paper by A.L. Despotuli, A.V. Andreeva and B. ...

with mobile Ag⁺ and Cu⁺

cation An ion () is an atom or molecule with a net electrical charge. The charge of an electron is considered to be negative by convention and this charge is equal and opposite to the charge of a proton, which is considered to be positive by conven ...

s include KAg₄I₅, NH₄Ag₄I₅, K_1−xCs_xAg₄I₅, Rb_1−xCs_xAg₄I₅, CsAg₄Br_1−xI_2+x, CsAg₄ClBr₂I₂, CsAg₄Cl₃I₂, RbCu₄Cl₃I_{2 and} KCu₄I₅.

References

{{rubidium compounds Metal halides Iodides Rubidium compounds Silver compounds Alkali metal iodides