41. Crystallography - New World Encyclopedia crystallography is the experimental science of determining the arrangement of atoms in solids. In older usage, it referred to the scientific study of crystals. http://www.newworldencyclopedia.org/entry/Crystallography

Crystallography From New World Encyclopedia Jump to: navigation search Previous (Crystallization) Next (Ctenophore) Structure determination by X-ray crystallography. Crystallography is the experimental science of determining the arrangement of atoms in solids . In older usage, it referred to the scientific study of crystals Before the development of X-ray diffraction crystallography, the study of crystals was based on their geometry. It involved measuring the angles of crystal faces relative to theoretical reference axes (crystallographic axes), using a goniometer, and establishing the symmetry of the crystal in question. Crystallographic methods now depend on the analysis of the diffraction patterns that emerge from a sample that is targeted by a beam of some type. The beam is not always electromagnetic radiation , although X-rays are the most common choice. For some purposes, electrons or neutrons are used, which is possible due to the wave properties of the particles. Crystallographers often explicitly state the type of illumination used when referring to a method, as with the terms X-ray diffraction

42. Krystalografia Studies of structures and phase transitions. http://alpha.uni.opole.pl

43. Crystallography Reciprocal Net is funded by the U.S. National Science Foundation as part of the National Science Digital Library project. http://www.reciprocalnet.org/edumodules/crystallography/index.html

Welcome to Reciprocal Net! Become a Partner Search Structure Contact Us Reciprocal Net ... Help Reciprocal Net is funded by the U.S. National Science Foundation as part of the National Science Digital Library project. You are here : Reciprocal Net Learn About Learn About: Crystallography Learning Modules Resources X-rays are electromagnetic radiation, similar to visible light, but occurring at a much shorter wavelength. While visible light ranges from 4000 to 7000 Angstroms (an Angstrom is 1/10,000,000,000th of a meter), X-rays routinely used in crystallography have a wavelength of 0.7 to 1.7 Angstroms. Visible light, infrared heat, and X-rays are all part of the Electromagnetic Spectrum. We are able to "see" objects with visible light because the objects scatter the light in all directions. Our eyes are capable of differentiating the different wavelengths (or color) and thus an image can be constructed in our mind. We are able to examine crystals with X-rays for a similar reason. Each atom in a molecule consists of a nucleus surrounded by electrons, the number of electrons determined by the atomic number of the element and the charge on the atom. The electrons present scatter the X-rays in all directions. The intensity of scattering from a given atoms is dependent largely on the number of electrons, and is represented by the "atomic scattering factor" for the element. If a periodic array of atoms is present, constructive and destructive interference will result, and we will observe diffraction only in certain directions and for given orientations of the periodic array. Since crystals consist of molecules arranged in a periodic way, a crystal acts as a nearly perfect diffraction grating for electromagnetic radiation in the X-ray region.

44. USF - Uppsala Software Factory Software for macromolecular crystallography and structural biology. Many of these programs collaborate with O (see there). http://alpha2.bmc.uu.se/~gerard/manuals/

Sorry, this page is designed for a frames-capable browser. You can still use the menu to navigate through our site.

45. Crystallography crystallography crystallography most often refers to the experimental methods used to determine the arrangement of atoms in solids. More traditionally, it is the scientific study http://www.fact-index.com/c/cr/crystallography.html

Main Page See live article Alphabetical index Crystallography Crystallography " most often refers to the experimental methods used to determine the arrangement of atoms in solids. More traditionally, it is the scientific study of crystals. Crystallographic methods all rely on the analysis of the diffraction patterns that emerge from a sample that is targetted by a beam of some type. The beam is not always electromagnetic radiation , even though X-rays are the most common choice. For some purposes electrons or neutrons are used, which is possible due to the wave properties of particles that are described by quantum mechanics . Crystallographers often explicitly state the type of illumination used when referring to a method, as with the terms X-ray diffraction, neutron diffraction and electron diffraction. Crystallography by itself typically implies X-rays. Crystallography is used to generate a kind of image of how the atoms in a material are arranged. The most familiar way to generate an image is with a lens , such as the lenses that a microscope uses to image the fine features of a sample. But the wavelengths of radiation employed by microscopes are long compared both to atomic bond lengths and to the sizes of

46. GSAS Notes Set of programs for the processing and analysis of both single crystal and powder diffraction data. http://www.ncnr.nist.gov/programs/crystallography/software/gsas.html

Home XTAL Instruments Search ... SiteMap Information about GSAS GSAS (General Structure Analysis System) is a comprehensive system for the refinement of structural models to both x-ray and neutron diffraction data. The GSAS package can be used with both single-crystal and powder diffraction data (Rietveld analysis), even both simultaneously. Neutron data can be either from single-wavelength instruments, or for those a bit more masochistic, time-of-flight instrumentation. Up to 99 different sets of data can be modeled using mixtures of up to 9 different phases. GSAS has been created by Allen C. Larson and Robert B. Von Dreele of Los Alamos National Laboratory. Executable versions of GSAS are distributed more-or-less freely (see the friendly message from the Regents of the University of California, below), but the source code is not distributed (don't complain to me on this one, I agree with you). Where do I get GSAS? downloads page for instructions and links. Note that there may be more recent versions of GSAS on the primary GSAS distribution sites: UK http://www.ccp14.ac.uk/ccp/ccp14/ftp-mirror/gsas/public/gsas/

47. Crystallography - Definition And More From The Free Merriam-Webster Dictionary Definition of word from the MerriamWebster Online Dictionary with audio pronunciations, thesaurus, Word of the Day, and word games. http://www.merriam-webster.com/dictionary/crystallography

48. ConfometRx - Crystallography GPCR crystallography. Until recently, the only highresolution GPCR crystal structures were of bovine rhodopsin. Structural analysis of GPCRs for hormones and neurotransmitters has http://www.confometrx.com/crystallography.php

@import "mainStyles.css"; Crystallography Skip navigation ConfometRx Home About ConfometRx Programs ... Contact GPCR Crystallography AR paves with way for obtaining structures of other GPCRs. ConfometRx has obtained the exclusive licensing rights for GPCR-T4Lysozyme fusion technology from Stanford University, and will provide this technology and its expertise in GPCR expression, structural engineering, biochemistry and crystallography on a contract/collaborative basis to partners in the biotechnology and pharmaceutical industries. For more information, please contact us. Home About ConfometRx Programs ... BACK TO THE TOP Website by Jason Kobilka

49. Phenix Software suite for the automated determination of macromolecular structures using X-ray crystallography and other methods. http://www.phenix-online.org/

New Phenix version 1.6.4 now available P ython-based H ... tallography Search phenixbb archives: PHENIX is a new software suite for the automated determination of macromolecular structures using X-ray crystallography and other methods. Citing PHENIX: PHENIX: a comprehensive Python-based system for macromolecular structure solution. P. D. Adams, P. V. Afonine, G. Bunkóczi, V. B. Chen, I. W. Davis, N. Echols, J. J. Headd, L.-W. Hung, G. J. Kapral, R. W. Grosse-Kunstleve, A. J. McCoy, N. W. Moriarty, R. Oeffner, R. J. Read, D. C. Richardson, J. S. Richardson, T. C. Terwilliger and P. H. Zwart. Acta Cryst. Download the latest official release ( ) [First request download password Help: FAQ Mailing List Subscription List Archives Report a Bug ... Email for Help Using PHENIX (release 1.6.4): Full Documentation PDF - Assessing data quality with phenix.xtriage - Automated structure solution with AutoSol - Automated molecular replacement with AutoMR - Automated model building and rebuilding with AutoBuild - Automated ligand fitting with LigandFit - Structure refinement with phenix.refine

50. Math Forum: Alejandre - Math Unit - Crystals Real World Viewing Crystals Contents Polyhedra in the Classroom Suzanne's Math Lessons crystallography Crystal Systems crystallography is a relatively new http://mathforum.org/alejandre/workshops/crystal.html

Real World - Viewing Crystals Contents Polyhedra in the Classroom Suzanne's Math Lessons [Crystallography] [ Crystal Systems Paper Nets Crystallography is a relatively new science. Rene-Just Hauy, who lived in the late 1700s to early 1800s, helped to make crystallography a mathematically exact science by classifying crystals with certain geometric shapes. Christian Westfeld (1746-1823) defined the concept of the unit cell. Christian Weiss (1780-1856) divided crystals into the different crystal systems that are used for classification today. Crystals form when changing temperatures beneath the earth's surface first melt a mass of molecules and atoms, then cool them slowly. As they cool, the atoms arrange themselves in symmetrical lattices. Simple molecular structure is the basis of a crystal's form. Crystals take shape according to the way in which their atoms combine. These atoms create regular geometric patterns because they always align themselves in the same way at a given temperature. A crystal, like a pattern, must have a shape that could extend or repeat itself in all directions indefinitely. That is why the faces of a crystal can only have certain shapes; they could not have anything but the symmetries in the patterns.

51. Crystallography Centre Windows Software for crystallography and Molecular Modelling from National University of Ireland. http://www.nuigalway.ie/cryst/software.html

52. Crystallography Open Database All data on this site have been placed in the public domain by the contributors http://www.crystallography.net/search.html

Search (Output limited to 300 entries maximum, see the hints and tips text (1 or 2 words) 1 to 8 elements NOT these elements volume min and max strict number of elements a (min - max) b c alpha beta gamma All data on this site have been placed in the public domain by the contributors Go to the upload page Go to the main page

53. X-tal Protocols Manual with information about (membrane) protein crystallization for X-ray crystallography. http://www.xtal-protocols.de

Introduction. Xtal-protocols the online www manual with information about (membrane) protein crystallization for X-ray crystallography. What has been done: 23-02-04 Changed to a new provider. Changed the layout of all the pages. 01-08-09 Changed to a new money provider. This means I have a better access to my hompage. But I stopped working on protein crystallization for X-ray crystallography. What I still want to do: Extending the page about screening for crystallization conditions. Score: include more pictures. Detergent: concentration determination of detergents. Expression of proteins in E. coli For information, comments, remarks but not for spam: E-mail: webmaster at xtal-protocols.de

54. Crystallography Home Educational module for use by researchers, teachers and students, provided by Kent Ratajeski, University of West Georgia. http://serc.carleton.edu/research_education/crystallography/

@import "/styles/layout_cutting_edge.css"; @import "/styles/base.css"; @import "/styles/cretaceous_look.css"; Teaching Mineralogy with Crystal Structure Databases and Visualization Software Integrating Research and Education Moving Crystallographic Instruction into the Digital Age Related Links Cutting Edge: Mineralogy - a collection of materials for teaching mineralogy Geochemical Instrumentation and Analysis - a collection of resources regarding geochemical instruments and techniques Cutting Edge: Petrology Analytical Instrument Registry Introduction Perception and understanding of three dimensional crystal structures is a source of difficulty for many introductory students of mineralogy. Traditionally, physical models of crystal structures (e.g., "ball and stick" and polyhedral models) have been used to help students better visualize the complex arrangements of atoms within crystalline materials. With the advent of newer computational and graphics technology, computerized virtual modelling of crystal structures and access to large crystal structure databases are now available to supplement traditional tools and methods of crystallographic instruction. We believe that the full potential of crystal structure databases and visualization software for enhancing the teaching of crystallography has not been fully explored. In most mineralogy classes, such tools are used to illustrate concepts in crystallography and crystal-chemistry, but these sessions are mostly controlled by the instructor. The students may or may not have the ability to manipulate the crystal models themselves to more fully interact with the material and form their own learning experiences; such direct interaction with models has been found to effectively aid spatial learning

55. Crystallography - Definition crystallography (from the Greek words crystallon = solid and graphein = write) is the experimental science of determining the arrangement of atoms in solids. http://www.wordiq.com/definition/Crystallography

Crystallography - Definition Crystallography (from the Greek words crystallon = solid and graphein = write) is the experimental science of determining the arrangement of atoms in solids . In older usage, it is the scientific study of crystals Crystallographic methods all rely on the analysis of the diffraction patterns that emerge from a sample that is targeted by a beam of some type. The beam is not always electromagnetic radiation , even though X-rays are the most common choice. For some purposes electrons or neutrons are used, which is possible due to the wave properties of particles that are described by quantum mechanics . Crystallographers often explicitly state the type of illumination used when referring to a method, as with the terms X-ray diffraction, neutron diffraction and electron diffraction. X-rays are useful for visualizing the electron clouds around atoms, whereas neutron diffraction methods will reveal the atomic nuclei. Thus far, electron diffraction has not been widely used. Crystallography by itself typically implies X-rays.

56. -Xavier Siebert----------- of research projects in crystallography and related fields of biophysics....... http://biophysics.med.jhmi.edu/amzel/people/siebert/

57. Crystallography - Definition And More From The Free Merriam-Webster Dictionary Definition of word from the MerriamWebster Online Dictionary with audio pronunciations, thesaurus, Word of the Day, and word games. http://www.merriam-webster.com/medical/crystallography

58. Crystallography Open Database A project accommodating crystal structure atomic coordinates prior to their publication. It is intended to give faster access to the latest structure determinations, openly. http://sdpd.univ-lemans.fr/cod/

Please redirect there : www.crystallography.net Crystallography Open Database

59. Rigaku Supplier of equipment for X-ray spectrometry, diffraction, and optics, as well as small molecule and protein crystallography. http://www.rigaku.com

60. X-Ray Crystallography Notes Notes on crystallography Table of Contents. Scattering and Diffraction XRay Scattering; Compton Scattering http://xrayweb.chem.ou.edu/notes/crystallography.html

Crystallography Table of Contents Scattering and Diffraction X-Ray Scattering Compton Scattering Interference Bragg's Law Crystals and their Properties Crystals Families of Planes Reciprocal Lattice Lattice Relationships ... Ewald Sphere Crystals Structures Intensity Relation Structure Factor Electron Density Phase Problem ... Calculated Structure Factor Scattering and Diffraction in Practice Scattering Factor Displacement Factor Anomalous Scattering Kinematic and Dynamic Diffraction ... References Much of the material presented below follows Chapter 3 of "Fundamentals of Crystallography" prepared by Carmelo Giacovazzo; see the Journal of Chemical Education Crystallography book shelf An excellent web site covering X-ray diffraction methods is available at: http://www.xtal.iqfr.csic.es/Cristalografia/index-en.html Introduction When X rays were discovered in 1895 , their exact nature was not known. The question posed at the time was "are X rays particles or are they waves like visible light?" Showing that X rays could diffract would prove that X rays have a wave-like nature.

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