Question

Q1- MgO crystal has FCC structure with lattice dimension of 0.42 nm and the ionic radii of 0.065 nm for Mg and 0.146 nm for 0. Calculate the packing efficiency. Q2- Find the intersects with x,y,z if the Millar indices are (1 1 1) for the cubic cell. Then sketch the plan Q3- What is the lattice dimension for Barquim (Bq) which has simple cubic structure if the molar volume 22.22 cm3 Q4- The spacing of one set of crystal planes in NaCl is d = 0.282 nm. A monochromatic beam of X-rays produces a Bragg maximum when its glancing angle with these planes is 0 = 7º. Assuming that this is a first order maximum (n = 1), find the wavelength of the X- rays

Answer 1

2) (ch, k, l) =(1,1) Miller indeces, .. Intercepts as =(1,',1) 1 I ch 1 I y 4) d =0.282 nm = 7 ° h = 1 using bragg's equation nd ad Sino ita = 2x0,282x10 "(Sin 7°) d =(6.87810-1 (wavelength of t-ray) m