Unpublished paper, 'On fluoride of silver. Part I' by George Gore

Description

Gore discusses the formation, preparation, analysis, composition, common physical properties, and chemical behaviour of fluoride of silver. The salt was prepared by treating pure silver carbonate with an excess of pure aqueous hydrofluoric acid in a platinum dish, and evaporating to dryness, with certain precautions. The salt thus obtained invariably contains a small amount of free metallic silver, and generally also traces of water and of hydrofluoric acid, unless special precautions mentioned are observed. It was analyzed by various methods: the best method of determining the amount of fluorine in it consisted in evaporating to dryness a mixture of a known weight of the salt dissolved in water, with a slight excess of pure and perfectly caustic lime in a platinum bottle, and gently igniting the residue at an incipient red heat until it ceased to lose weight. By taking proper care, the results obtained are accurate. The reaction in this method of analysis takes place according to the following equation, 2AgF + CaO = CaF2+2Ag + O. Sixteen parts of oxygen expelled equal thirty-eight parts of fluorine present. One of the methods employed for determining the amount of silver consisted in passing dry ammonia over the salt in a platinum boat and tube at a low red heat, The results obtained in the various analyses establish the fact that pure fluoride of silver consists of 19 parts of fluorine and 108 of silver.

Note on front reads 'A condensed copy of this paper was printed in [Philosophical Transactions] 1870'. This paper was also abstracted in volume 18 of the Philosophical Transactions of the Royal Society as 'On Fluoride of silver.—Part I'.

Subject: Chemistry

Received 5 October 1869. Read 13 January 1870.

Reference number

AP/52/4

Earliest possible date

04 October 1869

Physical description

Ink on paper

Page extent

114 pages

Format

Manuscript