The thermal expansion of silver iodide and the cuprous halides

In contrast to the extensive studies performed on AgBr and AgC1 l i t t le effort has been made to unders tand the nature of s t ructural disorder in AgI, CuC], CuBr and CuI. This is p r imar i ly a consequence of the comparat ive s t ructural s impl ic i ty of AgC1 and AgBr, as Table 1 i l lustrates. In t r ins ic thermal disorder in AgBr and AgC1 has been previously discussed (Lawn, 1963a) and appears to be p redominan t ly Frenkel wi th 'mixed ' Frenkel and Schot tky types at high temperatures . Most evidence, par t icu lar ly the ionic t ranspor t phenomena (see for example Lidiard, 1957), does in fact appear to favour the Frenkel model in all silver and cuprous halides.