Advertisements
Advertisements
प्रश्न
In case of hcp structure, how are spheres in first, second and third layers arranged?
उत्तर
- Hexagonal close-packed structure is obtained by stacking two dimensional hexagonal close-packed layers.
- So, the spheres in the first layer are arranged to form two dimensional hexagonal close packing.
- The spheres of the second layer are placed in the depressions of the first layer. If the first layer is labelled as ‘A’ layer, the second layer is labelled as ‘B’ layer because the two layers are aligned differently.
- The spheres of the third layer are aligned with the spheres of the first layer. The resulting pattern of the layers will be ‘ABAB....’. This arrangement results in a hexagonal close-packed (hcp) structure.
APPEARS IN
संबंधित प्रश्न
Answer the following in brief.
Cesium chloride crystallizes in a cubic unit cell with Cl– ions at the corners and a Cs+ ion in the center of the cube. How many CsCl molecules are there in the unit cell?
Aluminium crystallizes in a cubic close-packed structure with a unit cell edge length of 353.6 pm. What is the radius of Al atom? How many unit cells are there in 1.00 cm3 of Al?
In ionic crystalline solid atoms of element Y form hcp lattice. The atoms of element X occupy one-third of tetrahedral voids. What is the formula of the compound?
An element has a bcc structure with a unit cell edge length of 288 pm. How many unit cells and a number of atoms are present in 200 g of the element? (1.16 × 1024, 2.32 × 1024)
Identify the INCORRECT match.
A compound of X and Y crystallizes in ccp structure in which the X atoms occupy the lattice points at the corners of cube and Y atoms occupy the centres of each of the cube faces. The formula of this compound is ____________.
The total volume occupied by particles m simple cubic unit cell is ____________.
The number of particles in 1 g of a metallic crystal is equal to ____________.
The vacant space in simple cubic lattice is ____________.
The coordination number of each sphere in simple cubic lattice is ____________.
The percentage of vacant space of bcc unit cell is ____________.
Which among the following crystal structures the edge length of unit cell is equal to twice the radius of one atom?
What is the edge length of fcc type of unit cell having density and atomic mass 6.22 g cm−3 and 60 g respectively?
Copper crystallises with fee unit cell. If the radius of copper atom is 127.8 pm, calculate the density of copper? (At. mass: Cu = 63.55 g mol-1)
What is the percentage of void space in bcc type of in unit cell?
An element crystallizes in a bee lattice with cell edge of 500 pm. The density of the element is 7.5 g cm-3. How many atoms are present in 300 g of metal?
Silver crystallizes in face centred cubic structure, if radius of silver atom is 144.5 pm. What is the edge length of unit cell?
The relation between the radius of the sphere and the edge length in the body-centred cubic lattice is given by the formula ______.
Calculate packing efficiency in face-centred cubic lattice.
A compound made of elements C and D crystallizes in a fee structure. Atoms of C are present at the corners of the cube. Atoms of D are at the centres of the faces of the cube. What is the formula of the compound?
The packing efficiency of bcc is ______.
A compound has a hep structure. Calculate the number of voids in 0.4 mol of it.
