De Sando and Lange made the first reliable determination of thecrystal structure of polonium by X-ray diffraction methods. Theyused Cu-Kalpha X-rays, which have a wavelength of lambda=1.54056angstroms (1 angstroms= 10^-10). One of the X-ray reflections,corresponding to the unit cell edge length, was observed at ascattering angle of theta=13.258 degrees. Using the Braggrelationship n(lambda)=2dsin(theta), obtain the unit celldimensions for Po (Assume n=1). Next, the X-ray diffraction patternindicated that Po exhibits a simple cubic unit cell structure.Given that the dominant isotope of Po (t1/2 = 138d) has an atomicmass of 209.0 amu (obtained by mass spectrometry), what value didDe Sando and Lange calculate for the density of polonium?
I am totally lost on this problem, so any help is greatlyappreciated!