Calcium vapour deposition

Reactive deposition has developed into a powerful technology over the last 30 years. It is historically interesting to note that in early studies, Soddy [388] found in 1907 that calcium vapour is highly reactive to most gases and that Langmuir [389] in 1913 investigated the formation of tungsten nitride by vapour-phase reaction of the elements. 

Cakhim.— Perfluorobut-2-yne is released in low yield when the glass-like matrix obtained by co-deposition of calcium vapour and perfluorobut-2-ene on a cold (-196 °Q surface, in vacuo, is allowed to warm up. Under similar circumstances, perfluoropropane does not react perfluoro-propene and -cyclobutene give only large amounts of polymer . The butene - butyne defluorination is believed to involve the intermediate CF,-CF C(CF,)-CaF. (See p. 427 for information on atomic Ca-C F reactions.)... 

The observed catalytic effect of the alkali metal carbonates and oxides and the alkaline earth oxides upon the gasification of the ESC deposit in water vapour again most probably derived from successive oxidation and reduction processes. A possible cycle carbonate-metal-hydroxide could be feasible at this temperature, at least for sodium, potassium and lithium (3) and conceivably also for cesium and rubidium. For barium and strontium the cycle could be between a higher and a lower oxide. Calcium, in contrast to barium and strontium, does not form a peroxide by oxidation of calcium oxide and in any case this would not be stable above 200°C, which could explain why calcium oxide was not an active catalyst. 

Starch had been added, then above the blue liquid a zone of an intense yellow colour appeared, with a peculiar strong smell. By distillation and drying the vapour with calcium chloride he condensed drops of dark red liquid, which he proved was a new element analogous to chlorine and iodine. He announced this in 2ipli cachete of 30 November 1825 deposited with the Paris Academy of Sciences. Berard announced the discovery to the Academy on 3 July 1826, and Balard published a full account. His paper is followed by a report of 14 August 1826 by Vauquelin, Thenard and Gay-Lussac saying ... 

---