Krypton description

For each of the following select an element from Period 4, potassium to krypton, that matches the description. 

In Table 15.5 the predicted equilibrium lattice constants and cohesive energies of the solid neon, argon, and krypton are compared with experiments. The results of the first-principle calculations are satisfactory, except for a value of cohesive energy for neon. As one can see, the theory overestimates the equilibrium lattice constant. Nevertheless, the updated theory [75] provides the adequate description of van der Waals bonded systems. 

Note that the reaction products with entries in Table 19.1 are much abbreviated compared with the analogous tables of earlier groups. Only xenon and krypton react with fluorine to produce fluorides. Therefore, instead of following the usual format of describing the hydrides, oxides, hydroxides, and halides of these elements (most of which do not exist), we adopt a historical description of the synthesis of xenon compounds and then briefly expand the discussion to include the small number of examples drawn from krypton and radon chemistry. 

The procedure described in this paper is for the recovery of fission product krypton from kilogram amounts of irradiated uranium-metal. A brief description of the operations involved is given below to point out methods which maybe applicable to smaller scale e3q>eriments. 

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