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- The scientific study of crystals. In 1912, it
- was found that the shape and size of the unit
- cell of a crystal can be discovered by
- X-rays, thus opening up an entirely new way
- of `seeing' atoms. This means of determining
- the atomic patterns in a crystal is known as
- X-ray diffraction. It has been shown that
- even purified biomolecules, such as proteins
- and DNA, can form crystals, and such
- compounds may now be studied by the same
- method. Another field of application of X-ray
- analysis lies in the study of metals and
- alloys. Crystallography is also of use to the
- geologist studying rocks and soils. Many
- materials were not even suspected of being
- crystals until they were examined by X-ray
- crystallography. By this method it has been
- found that many substances have unit cells or
- boxes which are exact cubes, for example
- ordinary table salt (sodium chloride).
-