Rays Measure The Distances Between Atoms or Ions

X-RAYS MEASURE THE DISTANCES BETWEEN ATOMS OR IONS 

While Max von Lane used crystals to perform an experiment with x-rays, William H. Bragg (1862-1942) and his son William Lawrence Bragg (1890-1971) used x-rays to determine the structures of crystals. In 1912 and 1913 the Braggs developed and applied the diffraction equation that bears their name  

Not only did the Braggs x-ray diffraction apparatus allow these critical measurements of distances, they helped confirm the reality of ions since, as determined by J.J. Thomson, the intensity of scattering was proportional to the number of electrons (furnishing, in effect, an additional confirmation of atomic numbers). 

FIGURE 316. William H. Bragg and his son William L. Bragg reversed von Laue s experiment and used x-rays to measure the distances between ions or atoms in crystals (see text), (a) Depicts the conditions for constructive interference of x-rays termed Braggs Law (b) schematic of Braggs s x-ray apparatus (WH. Bragg and W.L. Bragg, X-Rays And Crystal Structure, 4th ed., London, 1924). 

Bragg and WL. Bragg, X-Rays And Crystal Structure, 4th ed., Bell, London, 1924. 

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