Essays Tagged: "Crystal structure"

Why does water expand when it is frozen?

each other and the solid usually has a very ordered arrangement of molecules in what is known as a crystal lattice. Water is exceptional because it can maximize the attractive forces between its mole ...

(1 pages) 64 1 3.0 Dec/2002

Subjects: Science Essays

Solar power: photovoltaics The journey from photons to electrons

SiliconLarge numbers of silicon atoms, through their valence electrons, can bond together to form a crystal. In a crystalline solid, each silicon atom normally shares one of its four valence electrons ... h it shares its valence electrons.This regular, fixed arrangement of silicon atoms is known as the "crystal lattice." That's what forms the crystalline structure, and that structure turns out to be im ...

(6 pages) 45 0 3.0 Sep/2003

Subjects: Science Essays

ON THE PROBLEM OF CRYSTAL METALLIC LATTICE IN THE DENSEST PACKINGS OF CHEMICAL ELEMENTS

l properties. However, attempts have been made to explain directional metallic bonds, as a specific crystal metallic lattice.This paper demonstrates that the metallic bond in the densest packings (vol ... ent, it is impossible, as a general case, to derive by means of quantum-mechanical calculations the crystalline structure of metal in relation to electronic structure of the atom. However, Hanzhorn an ...

(7 pages) 28 0 3.7 Apr/2004

Subjects: Science Essays > Chemistry

An essay describing why water/gallium expand when frozen.

t gallium forms pentagonal structures before solidifying, then the pentagons combine into a complex crystal lattice structure, causing it to expand 3.1%. Not only is it one of the only elements/compou ...

(2 pages) 43 0 5.0 Dec/2004

Subjects: Science Essays > Physics

Allotropes of Carbon

tionally good field emitters.Amorphous carbon is the name used for carbon when it does not have any crystalline structure. Some short range order can be seen but there is no long range pattern of atom ... t and stress of the impact causes it to turn into diamond however it retains the graphite hexagonal crystal lattice. Lonsdaleite has a transparent brownish yellow color. It has a hardness of 7-8 on Mo ...

(3 pages) 9 0 3.0 May/2007

Subjects: Science Essays > Chemistry

Massing Grown Crystals

on the spot. In most solids, the molecules are set in a regular pattern, they are in the form of a crystal. When these crystals are heated, they melt to a certain temperature. This is called the melt ... the melting point until there is no more of that solid remaining. Some solids, like glass, have no crystal structure and no particular melting point, but they do become more pliable as it gets warmer ...

(4 pages) 11 0 3.0 Feb/2008

Subjects: Science Essays > Chemistry

Determining the Number of Moles of Water of Crystallization Associated With One Mole of Copper (II) Sulfate in a Hydrate CuSO4 * xH2O (s).

INTRODUCTION Many salts that have been crystallized from water solutions appear to be perfectly dry, yet when heated they discharge large q ... salt is used in the described experiment. RESEARCH QUESTIONWhat is the number of moles of water of crystallization associated with one mole of copper (II) sulfate, in the hydrate CuSO4 * xH2O (s)? Th ... rmal treatment ( heating and cooling) and the dependent variable is the number of moles of water of crystallization. A number of other variables can affect the final result of the experiment: whether ...

(7 pages) 19 0 5.0 Jan/2009

Subjects: Science Essays > Chemistry