- In chemistry and
mineralogy, 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. The word crystals originates
from the Greek word "Krystallos" meaning clear ice, and once referred
particularly to quartz, rock crystal.
- Crystalline structures
occur in all classes of materials, with all types of chemical bonds.
Almost all metal exists in a polycrystalline state; amorphous or
single-crystal metals must be produced synthetically, often with great
difficulty. Ionically bonded crystals can form upon solidification of
salts, either from a molten fluid or when it condenses from a solution.
Covalently bonded crystals are also very common, notable examples being
diamond, silica, and graphite. Polymer materials generally will form
crystalline regions, but the lengths of the molecules usually prevents
complete crystallization. Weak Van der Waals forces can also play a role
in a crystal structure; for example, this type of bonding loosely holds
together the hexagonal-patterned sheets in graphite.
- The defining property
of a crystal is its inherent symmetry, by which we mean that under
certain operations the crystal remains unchanged. For example, rotating
the crystal 180 degrees about a certain axis may result in an atomic
configuration which is identical to the original configuration. The
crystal is then said to have a twofold rotational symmetry about this
axis. In addition to rotational symmetries like this, a crystal may have
symmetries in the form of mirror planes and translational symmetries,
and also the so-called compound symmetries which are a combination of
translation and rotation/mirror symmetries.
- There are a few crystal
structures, notably the perovskite structure, which exhibit
ferroelectric behaviour. This is analogous to ferromagnetism, in that,
in the absence of an electric field during production, the ferroelectric
crystal does not exhibit a polarisation. Upon the application of an
electric field of sufficient magnitude, the crystal becomes permanently
polarised.
- Single crystal silicon
ingots are created with a crystal pulling process originally developed
by Mitsubishi Materials Silicon called the CZ (Czochralski) method.
Crushed high-purity polycrystalline silicon is doped with elements like
arsenic, boron, phosphorous or antimony and melted at 1400° in a quartz
crucible surrounded by an inert gas atmosphere of high-purity argon. The
melt is cooled to a precise temperature, then a "seed" of single crystal
silicon is placed into the melt and slowly rotated as it is "pulled"
out. The surface tension between the seed and the molten silicon causes
a small amount of the liquid to rise with the seed and cool into a
single crystalline ingot with the same orientation as the seed. The
ingot diameter is determined by a combination of temperature and
extraction speed.
- Crystals form when the
concentration of a solution is higher than the solubility of the
product. This of course is a thermodynamic process; however the
production of crystals is governed by kinetic mechanisms. This kinetic/
thermodynamic battle leads to a condition called supersaturation, a
condition where the concentration of the solution is higher than the
solubility product but where crystals have not been produced.
- Crystals find numerous
applications in research and modern technology. Knowledge of crystal
properties and of their magnitude is the determining factor in their
selection for a given purpose. In addition, measured properties of a
crystal are of theoretical interest. The mere existence of a property
provides information about crystal symmetry, while its actual value
allows comparison with theoretical values derived from a microscopic or
quantum-mechanical model.
- Photovoltaic modules
make up about two-thirds of the lowest achievable grid-connected system
prices that have been reported. In 2005 the average price of modules in
the reporting countries was around 4,5 USD per watt, an increase of less
than 5 % over the corresponding figure for 2004. Interestingly, a number
of countries reported a decrease in module prices from 2004 while other
countries reported almost no change. The widely discussed increase in
module prices appears to have been a largely European phenomenon in
2005, possibly due to the local pressures on demand.
- Lascas1 mining and
processing in Arkansas was stopped at the end of 1997, and in 2005, no
U.S. firms reported the production of cultured quartz crystals. Cultured
quartz crystal production capacity still exists in the United States
using imported and stockpiled lascas as feed material. In the past
several years, cultured quartz crystal was increasingly produced
overseas, primarily in Asia. Electronic applications accounted for most
industrial uses of quartz crystal; other uses included special optical
applications.
- Crystal growth
processes provide basic materials for many applications and are for
example one key technology in the chain of all manufacturing processes
for (opto-)electronic devices. The research and development of crystal
growth processes is driven by the demands which come from the specific
applications; but in common there is a need for an increase of crystal
dimensions, improved uniformity of therelevant crystal properties in the
micro- and macroscale and materials with new properties.
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General
Information
- Crystal
- Different Kinds of
Crystals
- Types of Crystals
- Physical Properties of
Crystal
- Crystal
structure
- Creating
Crystals
Production and
Processing
- Production of quartz
crystal in 2007
- Production of quartz
crystal in 2005
- Production of quartz
crystal in 2006
- Production of quartz
crystal in 2001
- Production of quartz
crystal
- Production of quartz
crystal in 2004
- New Manufacturing
Process for Crystals
- Modeling in Industrial
Silicon Wafer Manufacturing - From Crystal Growth to Device
Processes
- Manufacturing Process
of Cavan Crystal
- Inhibition of calcium
oxalate monohydrate by poly(acrylic acids) with different
end-groups
- Manufacturing Process
of Single Crystal Aluminum Oxide
- Manufacturing Process
of Crystal
- Silicon Crystal Growth
and Wafer Production
- Multiscale simulations
of industrial crystal growth
Crystal
Growth
- Visual Simulation of
Ice Crystal Growth
- Crystal Growth of
Optical Materials for Advanced Lasers
- Crystal Growth
- Growth of Mercuric
Iodide Crystals
- Growth features of
ammonium hydrogen d-tartrate single crystals
- Crystal growth and the
steady-state grain size during
high-energy ball-milling
- Crystal Growing
Bench
- Growth of Large KDP
Crystals in the Form of Plates
- Protein Crystal
Growth
- Modeling Snow Crystal
Growth
- Single crystal growth
of rare earth titanate pyrochlores
- Growth of
Crystal
Functions and
Properties
- Single Crystal
Piezoelectrics Properties
- Properties of Crystals
- Mechanisms of classical
crystal growth theory
- Crystal
Properties
- Liquid crystal
properties
- Magnetic Properties of
Crystal
- Quartz Crystal
Properties
- Properties of single
crystal
- Unmeasured crystal
properties
Crystal Polishing
Procedures
- Polishing slide for the
crystals
- Plastic crystal
polishing
- Crystal and Rock
Polishing
- Polishing Glass Pocket
Watch Crystals Methods
- Polishing Crystal
Procedure
Company
- Company from
Newjersey
- Company from
Russia
- Company from
Canada
- Company from
China
- Company from British
Columbia
Consultant
- Consultant from
Deutsche
- Consultant from
California
- Consultant from
London
- International
Consultant
Manufacturers and
Suppliers
- Aquamarine Crystal
Suppliers
- Calcite crystal
Suppliers
- Canada Suppliers of
Crystal
- China Manufacturers of
Crystals
- Crystal
Encounters
- Engraved Glass and
Crystal Wholesale Supplier
- Crystal Abrasives
Manufacturers
- Monoclinic crystal
Exporters
- Quartz Crystal
Exporters
- Crystal Manufacturers
- Topaz Stone
Suppliers
- Top Rock
- Trade Leads of
Crystals
- Triclinic crystal
Suppliers
- Wholesalers of
Crystal
- Wiccan Pagan
Suppliers
- Rose Quartz Crystal
Suppliers
Buyers
- Buying Leads of
Crystal
- Foreign Buyers of
Crystals
- Importers of
Crystals
- Buyers of Quartz
Crystals
Equipments
Suppliers
- Crystal acid
polishing machine Suppliers
- Crystal Cutting Machine
Suppliers
- Furnace Tube
Suppliers
- Manufacturers of
Heaters
- Crystal Polishing
Machine Manufacturers
- Suppliers of Vibratory
Feeder
Project
- Processes for Growing
Large, Single-Crystal Aluminum Nitride
- Crystal Giant
Project
- Growing crystals-
factors that affect the rate and the size - science Project
- The Pentacene
Project
- Light propagation in
photonic crystals
- Liquid Crystal Project
- New Liquid Crystal
Smart Window and its Production Process
- Surfaces and interfaces
of liquid crystals
- Growing Crystal Science
Project
- Growing Crystals
Safety and
Guides
- Guidelines for TRS Single Crystal Based Stacked
Actuators
- Guidelines for Laser Safety and Hazard
Assessment
- Guide to Polishing Crystals
- Useful Links of
Crystal
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Applications
- Organic Crystals for
THz Wave Applications
- Application of a Liquid
Crystal Tunable Filter to Near-Infrared Spectral Searches
- Development of Single
Crystal Fibers for Optical, Scintillation and Mechanical
Applications
- Light shutters from
antiferroelectric liquid crystals of bent-shaped molecules
- Frequency Behavior of a
Quartz Crystal Microbalance (Qcm) in Contact with Selected
Solutions
- Compact and portable
holographic camera using photorefractive crystals. Application in
various metrological problems
- Gallium Nitride-Based
Chemical Sensors
- Crystals in Biological
Applications
- Applications for
Crystals
- Crystals Used for the
Production of Cubic Zirconia
- Liquid Crystals-
Applications and Uses
- Magical Uses of
Crystals
- Crystals and their
Uses
- Uses of Crystals
- Laser Crystals
Applications
- Modification of
Hydroxyapatite Crystal Using IR Laser
Technology and
Techniques
- Development of Crystal
Growth Technology
- A
Crystal Collimation Experiment at the Tevatron
- Modern crystal
processing technology
- Determination of
coupled solvent mass in quartz crystal microbalance measurements using
deuterated solvents
- Surface adsorption of
CS on Quartz crystals
- Piezo printing
technology
- Manufacture the Next
Generation Liquid Crystal Display (LCD) Chips
- CERN Technology
Transfer
- Fujitsu Develops
Efficient Silicon-Crystal Production
Technology
-
- Crystal Growth
Techniques
- Smith and Cartz Crystal
Growth Techniques
- Crystallization
Techniques
Patent
- Process for producing
amethyst crystals
- Rod shaped apatite
crystals
- Method for producing
calcite-type calcium carbonate single crystal
- Method for diffracting
crystals
- Methods for controlling
crystal growth, crystallization, structures and phases in materials and
systems
- Method for the
preparation of single crystals of gadolinium gallium garnet
- Purified quartz and
process for purifying quartz
- Method for producing
crystals
Products
- Crystal Products
- Crystal Shree
- Crystal Decorative
Products
- Monolithic Crystal
Filter
- List of Crystal
Products
- Hand - cut beverage
glasses
- Crystal
Ornaments
- Surface Mount Tuning
Fork Quartz Crystal
Material
Safety Data Sheet
- Bismuth Germanate
Crystal
- Pine Crystal Bowlene
Toilet Bowl Cleaner
- Cadmium Tungstate
Scintillation Crystal
- Diamond
Crystal
- Quartz Crystal MSDS
- Ink Crystal Stamp
Pads
- Thallium Bromide
Optical Crystal
Market
- Trends in Photovoltaic
Applications Survey
- Quartz Crystal Market
Demand
- Market for Quartz
Piezoelectric Crystal
- Markets Expand for
Piezoelectric Ceramics
- Booming Crystal Market
- Devising a Crystal
Clear Future
- Jiangsu crystal market
shines brighter
- Market Information of
Quartz Crystal in Taiwan
- Market Information of
Quartz Crystal in South Korea
- Market for Swarovski's
crystal
Report
- New Materials Synthesis
and Crystal Growth
- Application of phase
conjugation to crystal fibre optics
- Single Crystal
Piezocomposite Transducer Materials
- Multiple Time Scale
Simulations of Metal Crystal Growth
- Silicon Float-Zone
Crystal Growth
- Survey report of
selected IEA countries about Photovoltaic Application
- Crystal Growth
Laboratory Annual Report
- Controlling crystal
evolution on the nanoscale
- Report for
Crystal
- Silicon and Crystal Timing Solutions Market
- Silicon Crystal Growing
Facility
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