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
1.AB2
2.A2B3
3.A2B5
4.A2B
Percentage of free space in cubic close packed structure and in body centered packed structure are respectively:
1. 48% and 26%
2. 30% and 26%
3. 26% and 32%
4. 32% and 48%
Packing fraction of simple cubic crystal lattice is
1. 38%
2. 74%
3. 68%
4. 52.4%
In which of the following crystals are alternate tetrahedral voids occupied:
1. NaCl
2. ZnS
3. CaF2
4. Na2O
In a metal oxide, the oxide ions are arranged in hexagonal close packing and metal ions occupy two third of the octahedral voids. The formula of the oxide is :
1. MO
2. M2O3
3. MO2
4. M2O
The edge length of fcc unit cell of NaCl is 508 pm. If the radius of cation is 110 pm, then the radius of the anion is :
1. 144 pm
2. 249 pm
3. 288 pm
4. 398 pm
A crystal is made of particle X, Y & Z. X forms FCC packing, Y occupies all octahedral
voids of X and Zoccupies all tetrahedral voids of X, if all the particles along one body
diagonal is removed then the formula of the crystal would be –
(1) XYZ2
(2) X2YZ2
(3) X5Y4Z5
(4) X5Y4Z8
In a hypothetical solid C atoms are found to form cubical close packed lattice. Aatoms occupy all tetrahedral vioids& B atoms occupy all octahedral voids. A and B atoms are of appropriate size, so that there is no distortion in CCP lattice of C atoms. Now if a plane as shown in the following figure is cut.
Then the cross section of this plane will look like.
(1)
(2)
(3)
(4)
In hexagonal close packing of sphere in three dimensions.
(1) In one unit cell there are 12 octahedral voids and all are completely inside the unit cell.
(2) In one unit cell there are six octahedral voids and all are completely inside the unit cell.
(3) In one unit cell there are six octahedral void and of which three are completely inside the unit cell and other three are partially inside the unit cell.
(4) In one unit cell there are 12 tetrahedral voids, all are completely inside the unit cell.
Diamond has face-centred cubic lattice. There are two atoms at (0,0,0) and coordinates.The ratio of the carbon-carbon bond distance to the edge of the unit cell is
(1)
(2) 4
(3)
(4)