Fluorine Bomb Calorimetry at Constant Volume

French workers have developed a series of double-compartment bombs of small volume in which the sample volume is initially separated from the larger gas volume (.48). This allows combustions to be carried out on 50-mg samples but at lower precisions than with the larger bombs. 

Only six other centers have operated similar metal bomb calorimeters, mainly modeled on the Hubbard design, and it is therefore of interest to note that Gross and co-workers have been intrepid enough to use a simple two-compartment glass apparatus separated by a break-seal for fluorine combustion (5 atm Fj). Their results were in excellent agreement with those obtained in metal bombs (107). 

Although most of the fluorine calorimetry has been done with the elements, it has been used to bum oxides, carbides, nitrides, and chal-cogenides and hence determine their heats of formation. In some instances it has proved superior to oxygen bomb calorimetry. Thus the oxidation of boron tends to be incomplete because of oxide coating, whereas fluorination produces gaseous boron trifluoride without surface inhibition. A summary of modem fluorine calorimetry results is assembled in Table III. 

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