
	Where results make sense

Topic: Crystal structure

Related Topics

Crystal system

Crystal

Triclinic

Rhombohedral

Cubic (crystal system)

Bravais lattice

Liquid crystal

Monoclinic

Space group

Orthorhombic

Crystallography

Lattice

Crystallographic point group

Crystallographic group

In the News (Fri 1 Jun 12)

EXECUTIVE POWER

Iran

ANALYSIS

Pakistan

Family compact

	Crystal - Wikipedia, the free encyclopedia
		A crystal is a solid in which the constituent atoms, molecules, or ions are packed in a regularly ordered, repeating pattern extending in all three spatial dimensions.
		Under ideal conditions, the result may be a single crystal, where all of the atoms in the solid fit into the same lattice or crystal structure but, generally, many crystals form simultaneously during solidification, leading to a polycrystalline solid.
		Which crystal structure the fluid will form depends on the chemistry of the fluid, the conditions under which it is being solidified, and also on the ambient pressure.
	en.wikipedia.org /wiki/Crystal (631 words)

	Crystal structure: Just the facts... (Site not responding. Last check: 2007-10-21)
		A crystal's structure and symmetry play a role in determining many of its properties, such as cleavage ((embryology) the repeated division of a fertilised ovum), electronic band structure (additional info and facts about band structure), and optical properties (additional info and facts about optical properties).
		The crystal system is the point group (additional info and facts about point group) of the lattice (the set of rotation and reflection symmetries which leave a lattice point fixed), not including the positions of the atoms in the unit cell.
		The space group (additional info and facts about space group) of the crystal structure is composed of the translational symmetries in addition to the symmetries of the point group.
	www.absoluteastronomy.com /encyclopedia/c/cr/crystal_structure.htm (745 words)

	Encyclopedia: Crystal structure
		Quartz crystal A crystal is a solid in which the constituent atoms, molecules, or ions are packed in a regularly ordered, repeating pattern extending in all three spatial dimensions.
		In mineralogy a crystal structure is completely described by its unit cell lattice parameters, its space group symbol and the positions of the atoms that, when operated on by the essential rotational and translational symmetry operations, will generate entire contents within the unit cell.
		An interactive virtual reality representation of a cubic closest-packed structure is presented, and the viewer is asked to determine types of holes present in the structure and the number of each type in the unit cell.
	www.nationmaster.com /encyclopedia/Crystal-structure (697 words)

	Crystal Structure
		Its structure is made up of parallel chains of octahedrons, which are in turn composed of a titanium ion surrounded by six oxygen atoms.
		It is the parallel chain structure of these octahedrons that produces the prismatic crystal habit typical of rutile.
		The structure of rutile is in fact very similar to that of a close-packed atomic structure.
	web.ukonline.co.uk /aplr/structure.htm (385 words)

	Intro to Minerals: Crystal Class and System
		For example, crystals of the holomorphic class of the isometric system possess inversion symmetry, three 4-fold axes of rotational symmetry, the characteristic set of four 3-fold axes of rotational symmetry which is indicative of the isometric crystal system, six 2-fold axes of rotational symmetry, and nine different mirror planes.
		The crystal forms of the remaining five crystal systems are the monohedron or pedion, parallelohedron or pinacoid, dihedron, or dome and sphenoid, disphenoid, prism, pyramid, dipyramid, trapezohedron, scalenohedron, rhombohedron, and tetrahedron.
		The rhombic pyramidal crystal class is thus a member of the orthorhombic crystal system, the tetragonal pyramidal class is a member of the tetragonal crystal system, and the trigonal and hexagonal pyramidal classes are members of the rhombohedral (trigonal) and hexagonal divisions of the hexagonal crystal system respectively.
	dave.ucsc.edu /myrtreia/crystal.html (4278 words)

	Diamonds \| American Museum of Natural History
		The repeating structural unit of diamond consists of 8 atoms which are fundamentally arranged in a cube.
		Using this cubic form and its highly symmetrical arrangement of atoms, diamond crystals can develop in a variety of different shapes known as "crystal habits." The octahedron, or eight-sided shape that we associate with diamonds is its most common crystal habit.
		Two exceptions are the flat form called a macle, which is actually a composite crystal, and etched crystals, which have rounded surfaces and, sometimes, elongated shapes.
	www.amnh.org /exhibitions/diamonds/structure.html (308 words)

	Chlorite
		This is a (100) projection of the crystal structure of clinochlore, a Mg-rich triclinic chlorite of the common polytype IIb4.
		Refinement of the crystal structure of a monoclinic ferroan clinochlore.
		Structures of intergrown triclinic and monoclinic IIb chlorites from Kenya.
	ruby.colorado.edu /~smyth/chlorite.html (4068 words)

	Crystal Structure Databases
		The crystal structure information includes mineral name, specification, crystal chemical formula, space group, unit cell parameters, coordinates, thermal factors and occupancy of atomic positions as well as literature references on crystal structure determination.
		This database is a sister to the American Mineralogist Crystal Structure Database (AMCSD) and contains all the data that is in the AMCSD as well as data that has been deposited by individuals and laboratories.
		Crystal structure data are downloadable in CIF format, and users may upload crystal data as CIF or REF files.
	serc.carleton.edu /research_education/crystallography/xldatabases.html (457 words)

	Crystal Structure and Crystallography (from crystals) -- Britannica Student Encyclopedia
		One of the first theories of the internal structure of crystals was advanced in the late sixteenth century, when Andreas Libavius suggested that mineral salts could be identified by studying the shapes of their crystal grains.
		Certain minerals, such as quartz and the gemstones, often occur as single crystals; synthetic single crystals of elements, especially silicon and germanium, are used in solid-state electronic devices such as transistors,...
		In today's world a crystal is commonly considered to be a solid object with symmetrically arranged flat surfaces that meet in straight lines and sharp corners.
	www.britannica.com /ebi/article-199357?ct= (712 words)

	Crystal Structure (Site not responding. Last check: 2007-10-21)
		The crystals are commonly large, single, and faultless.
		Crystals frequently twin; a famous twinning habit is the Japanese twin, where two crystals contact at a 90º angle.
		One is a scepter growth, where the top of a crystal bulges out from the rest of the crystal, and another is a phantom growth, where one crystal forms over another, leaving a ghosted form inside.
	www.geocities.com /quartz_project/crystallinestructure.html (128 words)

	Crystal Lattice Structures: Other Crystal Structure Web Sites
		The Structure of Solids from Purdue has a bit of a tutorial about unit cells, and a description of the 14 Bravais lattices.
		Crystal Structures of Binary Inorganic Compounds, molecules, organic compounds, and more.
		Mineral Crystal Structures from the University of Calgary.
	cst-www.nrl.navy.mil /lattice/others.html (662 words)

	Amazon.com: Crystal Structure Determination: Books (Site not responding. Last check: 2007-10-21)
		To solve a crystal structure means to determine the precise spatial arrangements of all of the atoms in a chemical compound in the crystalline state.
		Single crystal structure determination has become an important and extremely powerful tool not only for inorganic and structural chemists but for all kinds of chemists interested in the structures of their compounds.
		The absolute highlight is, however, the step-by-step explanation of a structure determination, where one can almost see the author sitting in front of his computer and struggling with one of his structures, explaining every step in detail.
	www.amazon.com /exec/obidos/tg/detail/-/3540206442?v=glance (1025 words)

	Crystal Structures (Site not responding. Last check: 2007-10-21)
		A crystal is a periodic array of atoms.
		The crystals in Figures 1.1a and 1.1b have equivalent symmetry groups, while some of the symmetries of the honeycomb lattice are different.
		For a complex structure the identification of the symmetry group may be a rather nontrivial task.
	solidstate.physics.sunysb.edu /book/prob/node3.html (2041 words)

	Crystal Structure (Site not responding. Last check: 2007-10-21)
		The objective of this lab is to learn more about the basic crystal structures that metal atoms form.
		The properties of metals are very dependent on their crystal structure.
		Depending on the type of hole, an interstitial atom should be approximately one third the size of the atom which makes up the crystal structure in order to "fit" well.
	matse1.mse.uiuc.edu /~tw/metals/a.html (459 words)

	Introduction to diffraction (Site not responding. Last check: 2007-10-21)
		To illustrate the symmetry of crystals, the Escher Web Sketch application can be explored first in order to get some insight into the law of symmetries of crystals and any other repeating pattern which can be found in a two-dimensional world.
		The internal structure of crystals can be obtained by the method of diffraction by X-rays which reveals the details of the structure on the atomic scale.
		The rest of the crystal structure beeing generated by periodic translations in the three dimensions of space.
	marie.epfl.ch /x-ray (1171 words)

	Crystal structure of a protein that plays a role in supplying nutrients to solid tumors identified
		Crystal structure of a protein that plays a role in supplying nutrients to solid tumors identified
		A structural biologist from the Virginia Commonwealth University Massey Cancer Center, in collaboration with researchers at Memorial Sloan-Kettering Cancer Center, has identified the crystal structure of a protein that plays a role in supplying nutrients to solid tumors.
		The structure of the protein, Ang2, will be published this week in "Structure" a peer-reviewed scientific journal.
	www.medicalnewstoday.com /medicalnews.php?newsid=24236&nfid=mnf (319 words)

	Ratio Web (Site not responding. Last check: 2007-10-21)
		The crystal structure can be searched in various ways; from crystal structure thumbnails, from Periodic Table, or from the name of the substance.
		Not only the unit cell (minimum repeating unit) of the crystal structure, you can also see the view when the cells are stack together.
		Photographs of the crystals are provided with their properties e.g.
	www.ratio.co.jp /english (177 words)

	Introduction to Cubic Crystal Lattice Structures (Site not responding. Last check: 2007-10-21)
		The body-centered cubic structure is built up of body-centered cubic unit cell containing two atoms in each unit cell, one atom from the eight, one-eighth portions of the eight corner atoms and one from the atom located in the center of the unit cell.
		Ionic crystals are composed of charged species and the ions of the compound have different sizes.
		This structure can be viewed two different ways: face-centered cubic in chloride ions with sodium ions in every octahedral hole, or as two interpenetrating face-centered cubic structures.
	www.okstate.edu /jgelder/solstate.html (538 words)

	Crystallography Home
		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.
		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 [Gabel and Sherwood, 1980].
	serc.carleton.edu /research_education/crystallography/index.html (389 words)

	Crystal Structures of Elements (Site not responding. Last check: 2007-10-21)
		This structure is exhibited by metals Ag, Al, Au, Cu, Ir, Ni, Pb, Pd, Pt, and Rh, as well as the noble gases Ar, Kr, Ne, and Xe.
		A diamond structure has a face-centered cubic arrangement of atoms plus more atoms (of the same element) in half of the tetrahedral holes.
		Graphite has a structure containing layers of atoms arranged at the corners of contiguous hexagons (not to be confused with hexagonal close packed).
	www.molecules.org /elements.html (391 words)

	ICSD for WWW
		Structure: Produces a VRML or PDB 3D-drawing of the crystal structure.
		In mixed crystals, atoms in identical positions are labelled by the letter of the most frequent element.
		PRE : Pressure at which the structure was determined (in MPa or units as given).
	icsdweb.fiz-karlsruhe.de /index.php (2642 words)

	Chemical Crystallography Oxford: Home
		Members of other groups within Chemistry are encouraged to do their own structural analyses, and space, computers and patient tuition are available for them in the laboratory.
		Our software, CRYSTALS (single crystal X-ray structure refinement and analysis) is used world wide and has been presented and demonstrated at many meetings and workshops.
		The long-term aims of our research are to build chemical and crystallographic knowledge into software which can be routinely use by chemists, and to provide novel software tools for professional crystallographers.
	www.xtl.ox.ac.uk (480 words)

	Structure Determination by Powder Diffractometry Course
		Learn how to determine a crystal structure from powder diffraction data with experts help.
		The diploma is attributed after a final examination consisting in the structure determination of an unknown compound in 2 weeks.
		Many samples, organic or pharmaceutical, as well as inorganic, cannot be prepared as crystals of suitable size for a standard structure determination (using a four-circles single crystal diffractometer).
	www.cristal.org /course (133 words)

	NIST Scientific and Technical Databases - NIST Structural Database
		The Inorganic Crystal Structure Database (ICSD) is produced cooperatively by the Fachinformationszentrum Karlsruhe(FIZ) and the National Institute of Standards and Technology (NIST).
		The ICSD is a comprehensive collection of crystal structure data of inorganic compounds containing more than 70,000 entries and covering the literature from 1913 to the present.
		To be included in the database, a structure has to be fully characterized, the atomic coordinates determined and the composition fully specified.
	www.nist.gov /srd/nist84.htm (284 words)

	Basic Semiconductor Crystal Structure
		The crystal structure of pure silicon is of course 3-dimensional, but that is difficult to display or to see, so the image to the left is often used to represent the crystal structure of silicon.
		To allow our silicon crystal to conduct electricity, we must find a way to allow some electrons to move from place to place within the crystal, in spite of the covalent bonds between atoms.
		A crystal with two regions as described is known as a semiconductor diode, and is the topic of the next page.
	www.play-hookey.com /semiconductors/basic_structure.html (914 words)

	Shape Software
		You enter the crystal axis lengths and angles, the symbol for the crystal class, and one face of each form (symmetry equivalent set).
		The main library (700+ crystals) and supplementary library (200+ crystals), are based on the historical sets of wooden models designed in the 19th century by P. Groth and marketed by F. Krantz.
		When converting to a sub-cell or to higher symmetry the positions of presumably coincident or superimposed atoms are averaged, and when converting to a super-cell or lower symmetry the extra symmetry-unique atoms which may be required are generated.
	www.shapesoftware.com (2154 words)

Try your search on: Qwika (all wikis)