Sodium metal crystallises in a body centred cubic lattice with a unit cell edge of 4.29 Å The radius of sodium atom is approximate:
1.86 Å
3.22Å
5.72 Å
5.72 Å
CsCl crystallises in body centred cubic lattice. If 'a' its edge length, then which of the following expression is correct?
Lithium forms body centred cubic structure. The length of the side of its unit cell is 351 pm. Atomic radius of the lithium will be
75 pm
300 pm
240 pm
240 pm
In a face centred cubic lattice, atom A occupies the corner positions and atom B occupies the face centre positions. If one atom of B is missing from one of the face centred points, the formula of the compound is:
A2B
AB2
A2B3
A2B3
The edge length of a face centred cubic cell of an ionic substance is 508 pm. If the radius of the cation is 110 pm, the radius of the anion is
144 pm
288 pm
398 pm
398 pm
A.
144 pm
For FCC lattice (assuming cation in octahedral void and anion in FCC)
a = 508 pm
(r+ + r-) = a/2 = 508/2 = 254 pm
(r+ + r-) = 254 pm
r- = 254-110 = 144 pm
Percentages of free space in cubic close packed structure and in body centred packed structure are respectively
48% and 26%
30% and 26%
26% and 32%
26% and 32%
A metal crystallises in a face centred cubic structure. If the edge length of its unit cell is'a', the closest approach between two atoms in metallic crystal will be
2a
Copper crystallizes in fcc with a unit cell length of 361 pm. What is the radius of copper atom?
108 pm
127 pm
157 pm
157 pm
In a compound atoms of element Y from ccp lattice and those of element X occupy 2/3rd of tetrahedral voids. The formula of the compound will be
X4Y3
X2Y3
X2Y
X2Y