Bindi, Luca Dipartimento di Scienze della Terra, Università di Firenze, Firenze, Italy.
Steinhardt, Paul J. Princeton Center for Theoretical Science and Department of Physics, Princeton University, Princeton, New Jersey.
- The search in nature
- What about the origin?
- Links to Primary Literature
- Additional Readings
The regularly repeating atomic arrangement in crystals is called periodic. The hexagons in a honeycomb lattice (Fig. 1a) or the square tiles in bathroom tiling are examples of periodic tessellations. According to the laws of mathematics discovered in the nineteenth century, periodicity can only occur for certain rotational symmetries, such that one-, two-, three-, four-, and sixfold symmetry are allowed, but crystals or periodic tilings with five-, seven-, eight-, or higher-fold symmetry axes are strictly forbidden. About thirty years ago, however, a new kind of material that violates these rules was hypothesized and dubbed quasicrystals (short for quasiperiodic crystals), and, independently, a synthetic example was discovered in the laboratory. Since then, over a hundred different quasicrystals have been made in the laboratory using highly controlled synthetic methods.
The content above is only an excerpt.
for your institution. Subscribe
To learn more about subscribing to AccessScience, or to request a no-risk trial of this award-winning scientific reference for your institution, fill in your information and a member of our Sales Team will contact you as soon as possible.
to your librarian. Recommend
Let your librarian know about the award-winning gateway to the most trustworthy and accurate scientific information.
AccessScience provides the most accurate and trustworthy scientific information available.
Recognized as an award-winning gateway to scientific knowledge, AccessScience is an amazing online resource that contains high-quality reference material written specifically for students. Contributors include more than 9000 highly qualified scientists and 43 Nobel Prize winners.
MORE THAN 8500 articles and Research Reviews covering all major scientific disciplines and encompassing the McGraw-Hill Encyclopedia of Science & Technology and McGraw-Hill Yearbook of Science & Technology
115,000-PLUS definitions from the McGraw-Hill Dictionary of Scientific and Technical Terms
3000 biographies of notable scientific figures
MORE THAN 19,000 downloadable images and animations illustrating key topics
ENGAGING VIDEOS highlighting the life and work of award-winning scientists
SUGGESTIONS FOR FURTHER STUDY and additional readings to guide students to deeper understanding and research
LINKS TO CITABLE LITERATURE help students expand their knowledge using primary sources of information