Silver crystal structures, lattice parameters

The electrical resistivity of silver, at 273 K, is 1.47 X 10 Om. Silver adopts the A1 structure with a cubic lattice parameter, ao, of 0.4086 nm. The velocity of electrons at the Fermi surface is 1.39 x 10 m s . Each silver atom contributes one electron to the structure. Calculate the relaxation time, t, and the mean free path. A, of the electrons. Compare A with the interatomic spacing of silver atoms in the crystal. 

The heavy metal pseudohtilides fall in this group since covalent forces are partially present. The structural parameters listed in Table 4 show that thallous azide, fulminate and cycmate are isostructural with the tetragonal alkali metal salts, while thallous thiocyanate is isostructural with the room temperature phase of potassium thiocyanate. The lattice constants of the salts axe all indicative of abnormally short metal-anion distances. The silver salts form an interesting series where the subtle interactions which result as a function of the electron affinity, electronic structure and size of the anions, stimulate somewhat predictable variations of crystal geometry. Silver azide is an example of a distortion of the tetragonal D4 (Fig. 1) lattice due to covalent metal-emion interaction which lowers the space symmetry of the crystal to D2 (29), while silver thiocyanate is mainly covalent with bidentate metal-anion chains... 

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