Can someone please help me with these quetions? Detailed answers would be highly
ID: 1001836 • Letter: C
Question
Can someone please help me with these quetions? Detailed answers would be highly appreciated. Thanks.
Elemental carbon forms either a graphite layer structure or a diamond cubic crystal structure. What type of bonding would you expect to find in elemental carbon and whether you think that is the type of bonding seen in both structures? b) Explain why the bonding in graphite allows you to write with graphite c) Diamonds arc one of the hardest materials known compared to graphite which is soft. Why is diamond so different? d) How do you think the carbon-carbon bond lengths in graphite compare to those in in diamond explain the differencesExplanation / Answer
a.
The most common type of bond formed by carbon is a covalent bond. Covalent bonds formed by carbon are carbon-carbon bonds and carbon-hydrogen bonds. Covalent types of bonding are seen in both graphite layer structure and diamond crystalline structure.
b.
In graphite, the individual carbon atoms link up to form sheets of carbon atoms. Each sheet of carbon atoms is translated by one-half of a unit such that alternate sheets are in the same position. Within each sheet every carbon atom is bonded to three adjacent carbon atoms that lie at the apices of equilateral triangles. This produces hexagonal rings of carbon atoms. Each carbon atom has four valence electrons available to participate in the formation of chemical bonds. Three of these electrons are used in forming strong covalent bonds with the adjacent atoms in the sheet.. The fourth electron is free to wander over the surface of the sheet. The spacing between the sheets of carbon atoms is greater than the diameter of the individual atoms. Weak bonding forces (van der Waals forces) hold the sheets together. Because these forces are weak, the sheets can easily slide past each other. The sliding of these sheets gives graphite its softness for writing.
c.
Diamond is different to graphite because in diamond carbon atoms are bonded in different way. In diamonds, each carbon atom is strongly bonded to four adjacent carbon atoms located at the apices of a tetrahedron. The four valence electrons of each carbon atom participate in the formation of very strong covalent bonds. These bonds have the same strength in all directions. This gives diamonds their great hardness.
d.
Bond length of graphite / bond length of diamond.
In graphite each C-atom is covalently bonded to three C-atom to give trigonal geometry. Bond angle in graphite is 1200 Each C-atom in graphite is sp2-hybridized. Three out of four valance electrons of each C-atom are used in bond formation while the forth electrons free to move in the structure of graphite. Basic trigonal units unite together to give basic hexagonal ring. In hexagonal ring C-C bond length is 1.42Ao
In diamond, the s orbital mixes with the three p orbitals to form sp3 hybridization. The four valence electrons are thus equally distributed among the sp3orbitals, while each orbital points to one of the four corners of a tetrahedron. The tetrahedral structure, gives strength and stability to the bonds. All the bonds in diamond are of the same length 1.54 Ao with the same bond angle (109.470).