Using the data for silver in Table 3.1, compute the interplanar spacings in nm for the
(a) (110) and
(b) (221) sets of planes.
Table 3.1 Atomic Radii and Crystal Structures for 16 Metals
Crystal Structurea
Atomic Radiusb (nm)
Metal
Aluminum
FCC
0.1431
Molybdenum
BCC
0.1363
Cadmium
HCP
0.1490
Nickel
FCC
0.1246
Chromium
BCC
0.1249
Platinum
FCC
0.1387
Cobalt
Copper
Gold
HCP
0.1253
Silver
FCC
0.1445
Tantalum
BCC
0.1430
Titanium
HCP
0.1445
Iron
Lead
0.1241
Tungsten
BCC
0.1371
FCC
0.1750
Zinc
HCP
0.1332
aFCC = face-centered cubic; HCP = hexagonal close-packed; BCC = body-centered cubic
To compute the interplanar spacings in nm for the (110) set of planes, we need to find the atomic radius of silver in Table 3.1. The atomic radius of silver is 0.1445 nm.
The interplanar spacing for the (110) set of planes can be calculated using the formula:
d = a / sqrt(h^2 + k^2 + l^2)
where d is the interplanar spacing, a is the lattice constant, and h, k, and l are the Miller indices of the planes.
For the (110) set of planes, the Miller indices are h = 1, k = 1, and l = 0.
Substituting the values into the formula, we get:
d = 0.1445 / sqrt(1^2 + 1^2 + 0^2)
d = 0.1445 / sqrt(2)
d = 0.1445 / 1.414
d ≈ 0.102 nm
Therefore, the interplanar spacing for the (110) set of planes in silver is approximately 0.102 nm.
To compute the interplanar spacings in nm for the (221) set of planes, we use the same formula.
For the (221) set of planes, the Miller indices are h = 2, k = 2, and l = 1.
Substituting the values into the formula, we get:
d = 0.1445 / sqrt(2^2 + 2^2 + 1^2)
d = 0.1445 / sqrt(9)
d = 0.1445 / 3
d ≈ 0.048 nm
Therefore, the interplanar spacing for the (221) set of planes in silver is approximately 0.048 nm.