![]() ![]() However, in the trace amounts encountered in this experiment, it might well have appeared colourless. Their observation of a colourless gas does not fit with the known observation that fluorine is a pale-greenish-yellow coloured gas. "heavy smell, not pungent or irritating, and thereby easily distinguishable from chlorine or fluoric acid"Īnd a corrosive sublimate ie HgCl 2. Sometimes, during these experiments with HgF 2 and adapted vessels, they managed to obtain a colourless gas which had a Litmus turned red, glass was attacked, gold was slightly affected and on one occasion appeared to have formed gold fluoride. Various substances were subjected to the action of the gas formed. On moving the receivers over the mouth of the generating vessel, the stoppers fell in, exposing the receivers to the contents of the vessel. Mindful of fluorine's perceived reactivity, they used receivers with stoppers, both also made from fluorspar. They then proceeded to use larger fluorspar vessels, equipped with external electrical heating, to generate the element in amounts sufficient to investigate its properties. In the first vessel, HgCl 2 formed, and, in the second vessel, they found gaseous HF. The Knox brothers heated the fluorides of mercury and the hydrofluate of ammonia in small vessels of fluorspar, which contained HgCl 2. They noted that Davy had used vessels made from fluorspar, presumably considering that this material was inert towards fluorine's reactivity. In 1836 the Irish Knox brothers, Thomas and George, decided to search for the elusive fluorine. However, he did not succeed in isolating fluorine.ĭavy's work, together with that of other chemists, led to the presumption in the first half of the 19th century that a new element was awaiting discovery, but that its reactivity would make its actual isolation very difficult. He postulated that fluorine had e ntered into combination with the platinum wire. Davy explained this in terms of the hydrofluoric acid being split into its elements. However, the platinum wire on the opposite side of the battery was rapidly corroded and became covered with a 'chocolate coloured powder'. Moreover, by analogy with calcium chloride, Ampère also suggested that fluorspar consisted of fluorine and calcium.Īfter electrolysing the hydrofluoric acid, Davy found some gas had been produced at the cathode which, by its combustibility, was inferred to be hydrogen. The composition of hydrofluoric acid was a topic of debate until around 1810 when André-Marie Ampère suggested that it had a marked similarity to hydrochloric acid. He named it fluoric acid (now known as hydrofluoric acid). He concluded, with the insight that makes him one of the giants of 18th century chemistry, that fluorspar contained a 'specific acid', that is, an acid with a unique property. Later, in 1771, Carl Wilhelm Scheele revisited Schwanhard's work and found that the inner surface of a glass retort became corroded. Paul Louyet and Jerome Nickles died during their investigations, presumably due to the effects of inhaling HF. George Knox and his brother, Thomas Knox, both suffered from hydrofluoric acid poisoning. Davy suffered injury to his eyes and fingernails. Sir Humphry Davy, Louis-Joseph Gay Lussac and Louis-Jacques Thenard all suffered intensely from the effects of inhaling hydrogen fluoride. Both the liquid and vapour are poisonous, with the liquid form causing deep burns. ![]() The precursor to elemental fluorine is anhydrous hydrogen fluoride, boiling point 19 oC. ![]()
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