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Ch.12 - Solids and Solid-State Materials
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All textbooksMcMurry 8th EditionCh.12 - Solids and Solid-State MaterialsProblem 142

Chapter 12, Problem 142

The alkali metal fulleride superconductors M3C60 have a cubic closest-packed (face-centered cubic) arrangement of nearly spherical C60 3- anions with M+ cations in the holes between the larger C603- ions. The holes are of two types: octahedral holes, which are surrounded octahedrally by six C603- ions; and tetrahedral holes, which are surrounded tetrahedrally by four C603- ions. (c) Specify fractional coordinates for all the octahedral and tetrahedral holes. (Fractional coordinates are fractions of the unit cell edge lengths. For example, a hole at the center of the cell has fractional coordinates 12, 12, 12.)

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Hello everyone today. We have the following problem, specify the point and fractional coordinates for all the zinc atoms and zinc fluoride, the unit cell of zinc fluoride shown below, fractional coordinates use fractions to specify locations in the unit cell. So we're gonna do this, we're gonna label each of these blue dots that represent a representative of zinc. So we're gonna go 1234. This middle will be five, then we'll do 678 and nine. So if we look at the first sinks position, this position is going to be zero or 101. And so why does it have three of those? Well, they're used well, points in a unit cell are going to be specified in a range on a three D coordinate system. And so that's going to be represented by our standard X. Y. And Z plane. That's going to be your ex R. Y. And then we're going to have our Z. Plane. And so that's what these coordinates stand for. If we were to further and analyze this unit cell position two would lead us with coordinates 001, Our third zinc Adam is going to be 011 For our 4th one. This is going to be the one that has the triple ones or 111. And if we look at our center this is going to be one half one half, one half four hour six or zinc or 6th zinc atom. That is going to be our 100 for our seventh. That is going to be all zeroes four zinc eight. That is going to be 010. And then lastly far as ink nine, that is going to be 110. And with that we have answered this question overall, I hope that this helped and until next time.
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The mineral wustite is a nonstoichiometric iron oxide with the empirical formula FexO, where x is a number slightly less than 1. Wustite can be regarded as an FeO in which some of the Fe sites are vacant. It has a density of 5.75 g>cm3, a cubic unit cell with an edge length of 431 pm, and a facecentered cubic arrangement of oxygen atoms. (d) Using X rays with a wavelength of 70.93 pm, at what angle would third-order diffraction be observed from the planes of atoms that coincide with the faces of the unit cells? Third-order diffraction means that the value of n in the Bragg equation is equal to 3.

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