The cubic crystal structure lattice parameter a 04nm

Info icon This preview shows pages 5–7. Sign up to view the full content.

View Full Document Right Arrow Icon
tetragonal structure. The cubic crystal structure, lattice parameter a 0 0.4nm, and a motif of Ba 2+ at 000, Ti 4+ at 1/2 1/2 1/2, O 2- at 1/2 0 1/2 and 1/2 1/2 0 and 0 1/2 1/2. The tetragonal structure (T) is closely related to the cubic structure (C) and the lattice parameters a T and c T do not differ greatly from a 0 . A powder photograph of BaTiO 3 taken at 20˚C with Cu-K α radiation ( λ =1.5418Å) shows two closely spaced lines at θ =22.73˚ and θ =22.49˚. The line at θ =22.73˚ has about twice the intensity of the line at θ =22.49˚. (a) Determine the unit cell dimensions of tetragonal BaTiO 3 and describe the six lattice parameters. (b) Determine the structure factor for the first four maxima (or diffracted peaks) observed in an X- ray diffractometer experiment where powdered cubic BaTiO 3 has been used. (c) Explain why the intensity ratio of the two closely spaced lines is found to be about 2:1. Re a)
Image of page 5

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Re b) Re c)
Image of page 6
3) List the expression for the intensity observed in diffraction peaks obtained from powder samples using the Powder X-ray diffractometer instument and clearly describe each factor in this expression. See textbook Cullity and Stock… Five of the six factors that affect the Intensity in diffraction peaks for Powder X-ray diffraction matter for the diffractometer instrument… Namely, Structure factor, Multiplicity factor, the Temperature factor and the combination of the Polarization factor and Lorentz Factor, the Lorentz-Polarization factor.
Image of page 7
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern