Societies and Academies

Abstract

LONDON. Royal Society, Mar. 1.—A. E. H. Tutton: (1) The hexahydrated double sulphates containing thallium. Thallium salts corresponding to the potassium, rubidium, caesium, and ammonium salts of the iso morphous series 122M ( 04J . 6H20 have been prepared. Four of them are double sulphates containing thallium as the metal, and magnesium, ferrous iron, manganese, or copper as the M-metals; six are double selenates. (2) The hexahydrated double selenates containing thallium. The six salts are those in which R is thallium and the M-metal is magnesium, nickel, cobalt, ferrous iron, manganese, or copper. The results of the whole investigation (both papers) agree in showing that, as previously proved, potassium, rubidium, and cassium salts of the great series invariably show crystal forms and properties which vary regularly with the atomic number of the alkali metal. The ammonium members, while showing no relation to atomic numbers or weights, resemble the corresponding rubidium salts containing the same M-metal so closely as to be practically iso-structural. Thallium salts invariably occupy a position well within the limits (as regards angles and constants) of potassium and caesium salts. Thallium salts, however, have one strikingly outstanding property, that of very high optical refraction, occasionally exceeding even that of monobromonaphthalene and yet more so that of carbon disulphide.