Question

18. Metallic tungsten adopts a bcc structure with density 19250 kg m? What is the length of the edge of the unit cell? 19. Classify the following material using the electronegativity data and a Ketelaar triangle: (a) V205, (b) LiF, (c) HCI, (d) Cu3Au. 20. Use radius-ratio rules and the ionic radii to predict structures of (a) Na20, (b) HgF2, (c) Mgo, (d) Beo.

Answer 1

Dear Student, Kindly refer to the solution of your first question.

Dear student, The density of the unit cell is given as; D = ZXM - 0 3 x NA whele cell z= number of atoms pe unit for BCC Steluctule. Z=2 D= Density in glum az edge length in an M = Mobe mass in g/mol NA = Avogadro's constant = 6.022x10² mott Given D=19250 kg/m3 = 19.25 94 cm - M = 183.84 al mol substitute the values in 19.25 g/cm 2x 183.84 g/mol as x 6.022x 10²3 mol a² = 2x 183.84 gholt - 19.25g um? & 6.022x10² mol! a3 = 3.172 x 10 a = 3/13-172 x 103 ans cm - a = 3.166108 cm - Best wishes OR = 3.16 Aº