Properties of vapour-deposited yellow arsenic films at various condensation conditions

Serious discrepancies in the values of important physical parameters obtained by various authors for the yellow modification of arsenic As₄ have made it necessary to carry out a thorough investigation of the effect of preparation conditions of As films on parameters. It is shown that there exist in reality two forms of yellow arsenic, the low-temperature one, obtained at condensation temperatures below 95 K, and the high-temperature one - being formed at condensation temperatures above 193 K, which accounts for the differences in parameters, as presented by different authors. Considering reports on yellow arsenic layers undergoing phase transition at temperatures below 80 K, one may possibly speak of the existence of at least three forms of solid molecular arsenic As₄.