i) 0,1,1 – 1,0,0 à [ -1 1 1 ]

ii) ½,2,½ - 0,0,0 à [ 1 4 1 ]

iii) 0,½ ,0 – 1,0,1 à [ -2 1 -2 ]

iv) 2,1,1 – 1,1,0 à [ 1 0 1 ]

v) 1/3,1,0 – 1,1,1 = -2/3,0,-1 à [ -4 4 2 -9 ]

vi) 1,1,1 – 1,-1,0 = 0,2,1 à [ -2 4 -2 3 ]

1. x à -1

y à 1 ( -1 1 0 )

z à ¥

2. x à ¥

y à 3/2 ( 0 2 3 )

z à 1

3. x à 1/3

y à 1/2 ( 3 2 1 )

z à 1

4. x à ¥

y à 1 ( 0 2 1 )

z à 2

5. a1 à 1

a2 à ¥ ( 1 0 –1 0 )

a3 à -1

c à ¥

6. a1 à 1

List the physical and mechanical characteristics of the four atomic bonding types. Rank the bonds from the strongest to the weakest. For each bond type, list an example material.

1. The Metallic Bond

• forms between metallic elements
• some metallic elements give up their valence electrons leaving a positively charge atom
• the positively charges atoms are held together by attraction of electrons, producing a metallic bond
• good electrical conductivity
• see Figure 2-4
• Rank: #3
• Example à Silver

1. The Covalent Bond

• atoms share electrons with two or more atoms
• atoms are arranged such that a directional relationship is formed
• materials with covalent bonds have poor ductility, poor electrical conductivity, and poor thermal conductivity
• see Figure 2-8
• Rank: #2
• Example à Silicon

1. The Ionic Bond

• occurs only when more then one type of atom is present in a material
• ionic bond occurs when one atom donates its valence electrons to a different atom, filling the energy shell of the second atom
• both atoms have acquired an electric charge and behave as ions
• the atoms that donates the electrons is known as the cation
• the atoms that receives the electrons is known as the anion
• poor electrical conductivity
• see Figure 2-9
• Rank: #1
• Example à NaCl

1. Van der Waals Bonding

• join molecules or groups of atoms by weak electrostatic attraction
• this attraction occurs between positively charges regions of one molecule and negatively charged regions of a second molecule
• Van der Waals bonding is a secondary bonding
• see Figure 2-11
• Rank: #4
• Example à Van der Waals bonds hold together long polymer chains in PVC

Give examples of a binary compound for which the second element is located in an interstitial site. Using a sketch, indicate the interstitial site type(s) (ocathedral, tetrahedral, etc.) and the basic unit type.

The type of site the interstitial atoms enters is based on the radius ratio of the two atoms. See Table 3-6. See Figure 3-21 for the location of the ‘cubic’, ‘octahedral’, and ‘tetrahedral’ sites in the SC, FCC, and BCC unit cells.