An Electron Diffraction Study on the Crystal Structure of a New Modification of Chromium

摘要: Fine particles of chromium were produced by evaporation and condensation in argon at low pressures (Kimoto et al. : Japan. J. appl. Phys. 2 (1963) 702). Electron diffraction studies have shown that the ordinary b.c.c structure when contains a small amount air or oxygen but they new is pure. The has cubic primitive lattice with constant 0 =4.588±0.001 A. unit cell eight atoms; probable space group Pm3; one atom occupies position (a) 000, (b) \(\frac{1}{2}\frac{1}{2}\frac{1}{2}\) remaining six atoms distribute themselves so on average one-quarter an each 24-fold (1) x y z ; where \(x{=}\frac{1}{4}-u\), = v , \(z{=}\frac{1}{2}+w\) parameters u =0.2/100, =4/100 w =1/100. This disordered atomic arrangement derivable from β-tungsten structure. shortest Cr-Cr distance is...