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प्रश्न
Why ionic crystals are hard and brittle?
उत्तर
The ionic compounds are very hard and brittle. In ionic compounds, the ions are rigidly held in a lattice because the positive and negative ions are strongly attracted to each other and difficult to separate. But the brittleness of a compound is now easy to shift the position of atoms or ions in a lattice.
If we apply pressure on the ionic compounds the layers shifts slightly. The same charged ions in the lattice come closer. A repulsive force arises between the same charged ions, due to this repulsion the lattice structure breaks down chemical bonding.
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संबंधित प्रश्न
Describe triclinic crystal lattice with the help of a diagram.
What is the formula of a compound in which the element Y forms ccp lattice and atoms of X occupy 1/3rd of tetrahedral voids?
Name the parameters that characterize a unit cell.
Which of the following parameters are correct for triclinic lattice?
(A) α = β = γ = 90° and a = b = c
(B) α ≠ β ≠ γ = 90° and a ≠ b ≠ c
(C) α = γ = 90°, β ≠ 90° and a ≠ b ≠ c
(D) α ≠ β ≠ γ ≠ 90° and a ≠ b ≠ c
For a crystal of sodium chloride, state:
1) The type of lattice in which it crystallises
2) The coordina~ion number of each sodium ion and chloride ion in the crystal lattice.
3) The number of sodium ions and chloride ions present in a unit cell of sodium chloride.
4) The structural arrangement of the sodium chloride crystaL
Complete the following statement by selecting the correct alternative from the choices given:
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(i) How many carbon atoms are present per unit cell?
(ii) What type of lattice does diamond crystallize in?
(iii) How many carbon atoms surround each carbon atom?
(iv) How are they arranged?
AB crystallises in a body centred cubic lattice with edge length' a' equal to 387 pm The distance between two oppositely charged ions in the lattice is:
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