Advertisements
Advertisements
प्रश्न
In case of hcp structure, how are spheres in first, second and third layers arranged?
Advertisements
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 one or two sentences.
Mention two properties that are common to both hcp and ccp lattices.
Answer the following in brief.
Calculate the packing efficiency of metal crystal that has simple cubic structure.
Calculate the packing efficiency for bcc lattice.
A substance crystallizes in fcc structure. The unit cell edge length is 367.8 pm. Calculate the molar mass of the substance if its density is 21.5 g/cm3.
A compound is formed by elements A and B. This crystallizes in the cubic structure when atoms A are at the comers of the cube and atoms B are at the centre of the body. The simplest formula of the compounds 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 ____________.
Which of the following contains the highest number of atoms?
The percentage of vacant space of bcc unit cell is ____________.
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?
1 mol of CO2 contains ____________.
Which of the following is INCORRECT?
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)
Silver crystallizes in face centred cubic structure, if radius of silver atom is 144.5 pm. What is the edge length of unit cell?
Gold crystallizes in face centred cubic structure. If atomic mass of gold is 197 g mol-1, the mass of unit cell of gold is ______.
AB is an ionic solid. If the ratio of ionic radius of A+ and B- is 0.52, what is the coordination number of B- ?
The relation between the radius of the sphere and the edge length in the body-centred cubic lattice is given by the formula ______.
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 ______.
