crystalline carbon

fullerene

A fullerene (also called a Bucky ball) is a form of carbon in which carbon atoms are arranged in a hollow sphere resembling a soccer ball (see Figure 1.4). Each sphere contains 60 carbon atoms, and each carbon atom is bonded to three others by single covalent bonds. The bonds are relatively weak, so fullerenes can dissolve and form solutions. Fullerenes were first discovered in 1985 and have been found in soot and meteorites. Possible commercial uses of fullerenes are under investigation. Fullerene Crystal

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graphite

Graphite is a form of crystalline carbon in which each carbon atom is covalently bonded to three other carbon atoms. The carbon atoms are arranged in layers, with strong bonds within each layer but only weak bonds between layers (see Figure 1.3). The weak bonds between layers allow the layers to slide over one another, so graphite is relatively soft and slippery. This makes it useful as a lubricant. Q: Why do graphites properties make it useful for pencil leads? A: Being slippery, graphite slides easily over paper when you write. Being soft, it rubs off on the paper, allowing you to leave marks. Graphites softness also allows you to sharpen it easily. (Imagine trying to sharpen a diamond!)

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diamond

Diamond is a form of carbon in which each carbon atom is covalently bonded to four other carbon atoms. This forms a strong, rigid, three-dimensional structure (see Figure 1.1). Diamond is the hardest natural substance, and no other natural substance can scratch it. This property makes diamonds useful for cutting and grinding tools as well as for rings and other jewelry (see Figure 1.2).

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what are the forms of carbon

Graphite is one of three forms of crystalline, or crystal-forming, carbon. Carbon also exists in an amorphous, or shapeless, form in substances such as coal and charcoal. Different forms of the same element are called allotropes. Besides graphite, the other allotropes of crystalline carbon are diamond and fullerenes. All three forms exist as crystals rather than molecules. In a crystal, many atoms are bonded together in a repeating pattern that may contains thousands of atoms. The arrangement of atoms in the crystal differs for each form of carbon and explains why the different forms have different properties. Click image to the left or use the URL below. URL: Q: How do you think the properties of diamond might differ from the properties of graphite? A: Diamond is clear whereas graphite is black. Diamond is also very hard, so it doesnt break easily. Graphite, in contrast, is soft and breaks very easily.

instructional diagrams

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questions

forms of crystalline carbon include

a) coal.

-->  b) graphite.

c) charcoal.

d) two of the above

the form of carbon in question 6 has been found in meteorites.

-->  a. true

b. false

diamonds are used for

a) lubricants.

b) jewelry.

c) blades.

-->  d) two of the above

the form of crystalline carbon in which each carbon atom is covalently bonded to three other carbon atoms is

a) diamond.

-->  b) graphite.

c) charcoal.

d) coal.

fullerenes are used to make soccer balls.

a. true

-->  b. false

diagram questions

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