aula #11 - moodle.up.pt · aula #11. atoms and molecules. intermolecular forces liquids and solids...

Aula #11

Atoms and Molecules

Intermolecular Forces Liquids and Solids

States of Mater

e.g. Plasma



Crystal structure

Molecular solids and covalent networks

Diamond Graphite

Layers of .. interactions

Network of covalent bonds (intermolecular interactions)


Molecules are packed with maximum interaction potential. Several

and complex types of intermolecular interactionMolecular solids

hydrogen bonding (Green)

π---π (magenta) interactions

Dispersive interactions


Molecules are packed with maximum interaction potential. Several

and complex types of intermolecular interactionMolecular solids hydrogen bonding (Green)

π---π (magenta) interactionsDispersive interactions

https://www.ccdc.cam.ac.uk/Community/csd-community/freemercury/

• Large number of SCXRD structures of “small” molecules

• CCDC database has ca. 1.000.000 entries

• Metal Complexes


https://www.ccdc.cam.ac.uk/Community/csd-community/freemercury/

X RAY(Experimental determination of structural parameters …powders and monocrystals)

Mercury

Mercury - Crystal Structure Visualisation, Exploration and Analysis Made Easy

Mercury offers a comprehensive range of tools for 3D structure visualization and the

exploration of crystal packing. With a long pedigree and over 10,000 downloads,

Mercury is firmly established as the visualiser of choice within the crystallographic

community.


Macro Molecules are packed with maximum interaction potential.

Several and complex types of intermolecular interactionPolymers

hydrogen bonding (Green)

π---π (magenta) interactions

Dispersive interactions

Fórmula (-CO-C6H4-CO-NH-C6H4-NH-)n

Kevlar (poliamida aromática)




Formula (-CH(C6H5)CH2-)n

PS . Poliestireno

Microstruture EPS !!

http://pt.wikipedia.org/wiki/Imagem:Styropian.JPG

http://upload.wikimedia.org/wikipedia/commons/b/bd/Polystyrene.png




Foams can be flexible or rigid, thermoplastic or physically foamed or chemically foamed

Close Cell Open Cell


shows a close-packed layer with maximum utilization of space

keeping the electroneutrality…Cation +…Anion - InteractionsIonic solids


A ceramic is a non-metallic solid material comprising an inorganic compound of metal, non-metal or metalloid atoms primarily held in ionic and covalent bonds.

The crystallinity of ceramic materials ranges from highly oriented to semi-crystalline, vitrified, and often completely amorphous (e.g., glasses)


Borosilicate Glass (Pyrex)80% SiO2, 13% B2O3, 4% Na2O, 3% Al2O3:


Structure

2nm

TiO2

Crystal 1

Border

Crystal 2

Amorphous Carbon

Ceramics


An amorphous solid does not possess a well-defined arrangement and long-range molecular order.

A glass fusion product of materials that has cooled to a rigid state without crystallizing

Crystallinequartz (SiO2)

Non-crystallinequartz glass


shows a close-packed layer with maximum utilization of space and

symmetry. Metallic bond (sea of electrons & core metallic ions)

Metallic solids



symmetry. Metallic bond (sea of electrons & core metallic ions)

Metallic solids

e.g. ZINC, Zn

Compact hexagonal structure (6 / mmm) (hexagon with one atom centered)

Each Zn atom is surrounded by 12 atoms in equidistant positions

-Crystal structure with high symmetry;



symmetry. Metallic bond (sea of electrons & core metallic ions)Metallic solids


Metal Alloys …Phase diagram …. Fe and C Alloy (steel)

IRONCARBONNICKELCHROMIUNMOLYBDENUM& OTHERs

METAL ALLOY:

Steel

IRONCARBON

Stainless steel

n (negative) Type p (positive) Type

Leads to an increased of number of electrons in conduction band.....

Donor atoms of Group XV, P As, Sb

Trivalent element promoting the formation of positive holes ..... Donor atoms of Group XIII, B, Al, Ga

Semiconductors

Semiconductors

EXTRÍNSECOS

n (negativo)

p (positivo)

Si ( 1.1 eV)

0.04 0.044 0.049

Sb P As

B Al Ga

0.0450.057

0.065

+

-

+ -

Band GAP

aula #11 - moodle.up.pt · aula #11. atoms and molecules. intermolecular forces liquids and solids...

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