2/10/2024 Crystal Growth

Copper sulphate crystal growth

using solution growth method.

SARANYA JOY
BASELIUS COLLEGE KOTTAYAM
 Introduction

A
crystal or crystalline solid is a solid material whose constituents (such
as atoms, molecules, or ions) are arranged in a highly ordered
microscopic structure, forming a crystal lattice that extends in all
directions.[1][2] In addition, macroscopic single crystals are usually identifiable by their
geometrical shape, consisting of flat faces with specific, characteristic orientations. The
scientific study of crystals and crystal formation is known as crystallography.

Early civilisations employed crystal sands to cut rock and stone, make jewellery and
ornaments and engrave. Synthetic crystals were more robust, cheaper, and quicker to
produce than natural crystals. Thus they rapidly found a market in many sectors:

• Semiconductor Watches - Watchmakers employ quartz, ruby, and

sapphire. Rolex watches have scratch-resistant sapphire glass. Synthetic ruby is
used in the watch and mechanical bearings.

• Cutting Diamonds and Dust - Diamond bits cut stone blocks and
decorative stones in industrial saws and ropes. Oil well drills employ diamond-
studded drill bits. Jewellers and lapidary artists utilise diamond saws, copper
laps with diamond dust, and diamond cleaning powder for jade and sapphire.

• Ruby-Laser - This 1960 red light beam has minimum divergence and is
strong. CD players, long-distance phones, surveys, and microsurgery use it. The
small ruby laser pointer helps college instructors in lectures. Lasers can cut steel
and drill diamonds.

Uses of Crystals in Technology

• Quartz crystals are used in sonar, ultrasound, radios, transistors,
semiconductors, and digital timepieces.

• They are used in electric guitars, microphones, and most digital electronics.

• They're used in ovens, barbecues, heaters, and lighters.

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The process of crystal formation via mechanisms of crystal growth is called
crystallization or solidification.[3] Crystals possess various properties, including:

Symmetry: Crystals exhibit symmetry in their atomic arrangement, which is

described by crystallographic point groups and space groups.

Lattice structure: Crystals have a regular and repeating three-dimensional

arrangement of atoms, ions, or molecules known as the crystal lattice.

Optical properties: Crystals can exhibit optical phenomena such as

birefringence, polarization, and optical activity.

Mechanical properties: These include hardness, cleavage, elasticity, and

brittleness, which depend on the crystal structure and bonding.

Electrical properties: Crystals can be insulators, semiconductors, or

conductors, depending on their atomic structure and bonding.

Thermal properties: These include thermal conductivity, specific heat

capacity, and coefficient of thermal expansion, which vary with crystal structure
and bonding.

Magnetic properties: Crystals can be diamagnetic, paramagnetic,

ferromagnetic, antiferromagnetic, or ferrimagnetic, depending on the

arrangement of magnetic moments within the crystal lattice.

Chemical properties: Crystals may have specific chemical reactivity and

solubility characteristics based on their composition and crystal structure.

There are several crystal growth techniques, including:

Czochralski method: Involves dipping a seed crystal into a molten material

and slowly pulling it out to form a single crystal.

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 Bridgman method: The material is melted in a crucible, and a seed crystal
is dipped in and slowly withdrawn, allowing a single crystal to form as the melt
solidifies.

Vapor phase growth: Crystals are grown from the vapor phase, either

through chemical vapor deposition (CVD) or physical vapor transport (PVT).

Solution growth: Crystals are grown from a solution or melt. Techniques

include the hydrothermal method and flux growth.

Zone melting : Involves passing a molten zone through a polycrystalline

material, allowing impurities to segregate.

Liquid phase epitaxy (LPE): Thin films or single crystals are grown by

depositing layers atom by atom from a supersaturated solution onto a

substrate.

Hydrothermal synthesis: Crystals are grown from a superheated aqueous

solution at high pressures.

These techniques are utilized based on factors such as the material being grown,
desired crystal quality, and application requirements.[4]

Prepration of solution

S ome amount of copper sulphate ( CuSO4 ) is taken and grinded to powder

form using a crusher. A glass beaker 25% filled with distilled water is taken
and the powdered CuSO4 about 50gms is added and stirred well until they get
dissolved completely using a magnetic stirrer. After the complete dissolving of the
solute in the solvent 50gms more of the solute is added and stirred, this addition of

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solute was repeated until maximum amount of solute that can be dissolved in the
solvent is reached . ie., this is repeated until the saturation of the solutions is achieved.

The saturated solution thus obtained at the room temperature is filtered out
into a clean beaker and kept in a safe place where it is affected by no disturbances. In
two days the solvent evaporates by a decent amount leaving some crystals sedimented
at the bottom of the beaker. The crystal formed is polycrystalline, which means that
the crystal formed is not a pure single crystal but is a crystal with is composed of many
small crystal clumbed together. A polycrystalline structure is obtained when the
nucleation rate is greater then the growth rate. The polycrystal formed is taken out
and broken down to many small single crystals.

The small single crystal is used as the seed crystal roughly of size 0.3cm in length
. The CuSO4 saturated solution is again prepared and filtered out , the seed crystal is
then tied to a thread and suspended in this saturated solutions and left undisturbed
for 10 days. After 10 days we observed that the seed crystal have grown to a single
crystal of size of about 1.7cm in length. The solution was made saturated again and
this large crystal was suspended in the new saturated solution for another 5days. After
these 5 days the suspended crystal had grown bigger one of the size of about 3cm in
length. We were satisfied with the size of the grown crystal so that the crystal was
taken out from the solution .

Fig 1.1

This figure shows the CuSO4 made by

solution growth technique.

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 Conclusion
It is observed that copper sulphate is the easiest salt that can be crystallized at room
temperature without any constraints. When we use warm water instead of the
normal water the crystal will grow much bigger in very less time.

Reference
1. Stephen Lower. "Chem1 online textbook—States of matter". Retrieved 2016-09-19.
2. Ashcroft and Mermin (1976). Solid State Physics.
3. https://www.vedantu.com/evs/uses-of-crystals
4. Crystal growth: processes and methods- P.S. Raghavan and P. Ramasamy, KRU publications

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