?In their book X-rays and crystal structures (which begins 'It is now two years since

Chapter 15, Problem P15B.4

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In their book X-rays and crystal structures (which begins 'It is now two years since Dr. Laue conceived the idea ...') the Braggs give a number of simple examples of X-ray analysis. For instance, they report that the reflection from 100 planes in KCl occurs at \(5.38^{\circ}\), but for NaCl it occurs at \(6.00^{\circ}\) for X-rays of the same wavelength. If the side of the NaCl unit cell is 564 pm, what is the side of the KCl unit cell? The mass densities of KCl and NaCl are \(1.99 \mathrm{~g} \mathrm{~cm}^{-3}\) and \(2.17 \mathrm{~g} \mathrm{~cm}^{-3}\) respectively. Do these values support the X-ray analysis?

Text Transcription:

5.38^circ

6.00^circ

1.99 g cm^-3

2.17 g cm^-3