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Chemistry question

Hi, can anyone please give me two allotropes each of two elements each. Any help would be greatly appreciated.

Soni
Student - Toronto, Ontario, Canada
2003

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If you will explain to me what an allotrope is, so that I know you understand the question, Soni, I will find two examples for you. It would be a disservice to you (and society) to post an answer you can submit to your teacher if you don't even know what the question means.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
2003

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2003

Some elements and a compound with 2 or more allotropic forms each:

Carbon � alpha-graphite (hexagonal, layered arrangement of atoms), beta-graphite (rhombohedral, layered), diamond (diamond cubic structure) and amorphous (glassy) forms. Graphite is soft and low in density. It can be converted to diamond, which is hard and dense, by great pressure (about 13 Gpa) at high temperature. Another form of carbon has the atoms arranged in "buckyballs".

Iron � ferrite (body-centered cubic structure) and austenite (face-centered cubic). Ferrite additionally has alpha and beta allotropes differing in magnetic properties. Heating ferrite above 912 C transforms it to austenite. This transformation and its reverse are important to the steel industry. Tin � gray tin (cubic) and white tin (tetragonal). White tin can convert to gray tin when cooled below 13.2 C; this transformation is the "tin pesting disease".

Silicon dioxide is a compound with multiple allotropes, including quartz (alpha and beta types), cristabolite, tridymite and fused silica glass.

Ken Vlach
- Goleta, California

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Soni,

Carbon has 3 allotropes: Graphite, Diamond and Buckminsterfullerene.
sulfur has 2: Rhombic and Monoclinic
Oxygen has 2: Oxygen and Ozone

Nigel D Gill, B.Sc. MIMF AIEM AMRSC
- Glasgow, Scotland
2003