Giant covalent and ionic structures form when many atoms are bonded together in repeating patterns. Giant covalent structures include carbon materials like diamond and graphite, which have carbon atoms bonded together in tetrahedral or planar arrangements. Silicon dioxide also has a giant covalent structure where silicon atoms are bonded to four oxygen atoms in a repeating pattern. Giant ionic structures form crystalline ionic compounds where ions are bonded via electrostatic forces, such as sodium chloride which contains sodium and chloride ions. These giant structures have high melting points due to the large amount of energy required to overcome the numerous bonds between constituent atoms.

1. Giant Covalent & Ionic
Structures
DR FARHAD M. ALI
MARCH 2023
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2. Giant structures
Either covalent or ionic
 Covalent: carbon (diamond, graphite);
silicon dioxide; polymer (made from non-
metals which form giant structures)
 Ionic:
giant metallic lattice: sodium and
aluminium as examples
giant ionic lattice: ionic compounds such
sodium chloride.
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3. What are giant covalent structures?
• When a large number of atoms are joined by
covalent bonds, it creates a giant covalent
structure.
• A giant covalent structure has lots of covalent
bonds linking several atoms in a regular
pattern, which forms a lattice.
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4. Carbon atoms in diamond form a tetrahedral
arrangement. Each Carbon atom bonded to four others.
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5. Diamond-it is pure carbon-
It is an allotrope of carbon
• All the properties of diamond is because of
the fact that the strong covalent bonds
extended in all directions through the whole
structure of the crystal
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7. Graphite-it is pure carbon
It is an allotrope of carbon
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8. Graphite-it is pure carbon
It is an allotrope of carbon
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9. Graphite-it is pure carbon
It is an allotrope of carbon
• Graphite is brittle as little energy is required
to break the weak induce dipole forces but,
• it still has a very high melting point as a lot of
energy is needed to break the large number of
covalent bonds.
• Graphite has a low density because the
distance between the layers is large. As the
layers in graphite are held together by weak
intermolecular forces, the layers are far apart.
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10. Graphene-it is pure carbon
Also an allotrope of carbon
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11. Graphene-it is pure carbon
Also an allotrope of carbon
 Graphene is technically composed of carbon
atom and a covalent bond that formed a
honeycomb pattern.
 is made of a single sheet of carbon
atoms arranged in a crystal lattice (like a
honeycomb pattern).
 It is the basic building block of graphite.
 show high melting points than many other
materials
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12. Silicon dioxide SiO2 (also known as silica)
This is the structure of SiO2.
This has a giant structure
This is just a tiny part of a giant structure extending on all 3
dimensions.
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13. Silicon dioxide SiO2
• When we look at the structure we see that the
silicon bonds to 4 oxygen atoms but why do
we say SiO2?
• The Silicon atom is bonded to 4 Oxygen atoms
and each Oxygen is bonded to 2 other silicon
atoms. This leads to a ratio of 1:2
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14. The physical properties of silicon
dioxide
• has a high melting point (around 1700°C).
• Very strong silicon-oxygen covalent bonds have
to be broken throughout the structure before
melting occurs.
• is hard. This is due to the need to break the very
strong covalent bonds.
• doesn't conduct electricity. There aren't any
delocalised electrons. All the electrons are held
tightly between the atoms, and aren't free to
move.
• is insoluble in water and organic solvents.
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15. Why do giant covalent structures have
high melting points?
• These structures have high melting points due
to the covalent bonds holding the atoms
together.
• It is very difficult to break down these bonds
when they are melted and they require a large
amount of energy (i.e. a high temperature) to
break the structure.
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16. Are giant covalent structures soluble
in water?
• These structures are insoluble due to their
strong covalent bonds.
• Therefore, these are generally inert and so do
not react with water, making it impossible to
dissolve
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17. Why do giant covalent structures not
conduct electricity?
• The structures are poor electrical
conductors of electricity because they do not
have free electrons to conduct electricity
through the molecule.
• However, graphite is an exception.
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18. Metallic Bonding-
• Metallic bonding is a type of chemical
bonding that arises from the electrostatic
attractive force between conduction electrons
(in the form of an electron cloud of
delocalized electrons) and positively charged
metal ions
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19. Metallic Bonding-
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21. Metallic Bonding-
• Most metals have high melting and boiling points-
• Since the attraction forces between the delocalised and
positive metal ions-this need high energy to overcome this
attraction.
• Metals are good conductors for heat and electricity-
• Since the mobile electrons can move throgh the structure,
carrying electricity.
• They are malleable: easily bent and shaped
• ductile: streched into wires
• Atoms of metal arranged in layers-when a forc is applied,
the layers can slid over each other-forming new bonds this
will leave the metal with a different shape.
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