Advertisements
Advertisements
प्रश्न
A cubic solid is made of two elements P and Q. Atoms of Q are at the corners of the cube and P at the body-centre. What is the formula of the compound? What are the coordination numbers of P and Q?
A cubic solid is made up of two elements P and Q. Atoms Q are present at the corners of the cube and atom P at the body centre. What is the formula of the compound?
Advertisements
उत्तर
It is given that the atoms of Q are present at the corners of the cube.
Therefore, number of atoms of Q in one unit cell = `8 xx 1/8`
= 1
It is also given that the atoms of P are present at the body centre.
Therefore, number of atoms of P in one unit cell = 1
This means that the ratio of the number of P atoms to the number of Q atoms, P : Q = 1 : 1
Hence, the formula of the compound is PQ.
The coordination number refers to the number of nearest neighbouring atoms surrounding a given atom. For P, since it is surrounded by Q atoms, we have:
Coordination number of P = 8
For Q, which is surrounded by P atoms, the coordination number is also:
Coordination number of Q = 8
Thus, the formula of the compound is PQ, and the coordination numbers of both P and Q are 8.
Since the lattice is body-centred cubic, the coordination number of each atom is 8.
Notes
Students should refer to the answer according to their questions.
संबंधित प्रश्न
What is the two dimensional coordination number of a molecule in square close packed layer?
How many lattice points are there in one unit cell of the following lattice?
Face-centred cubic
Ferric oxide crystallises in a hexagonal close-packed array of oxide ions with two out of every three octahedral holes occupied by ferric ions. Derive the formula of the ferric oxide.
The coordination number of AB having rock salt geometry is ____________.
Hexagonal close packed arrangement of ions is described as ____________.
Which of the following statement is not true about the hexagonal close packing?
With the help of a labelled diagram show that there are four octahedral voids per unit cell in a cubic close packed structure.
How can you best describe the elongated octahedral structure of blue vitriol, CuSO4.5H2O?
The octane number of Iso-octane is
The crystal system of a compound with unit cell dimensions a = 0.387, b = 0.387 and c = 0.504 nm and α = β = 90° and ϒ = 120° is
Total no. of voids in 0.5 mole of a compound forming hexagonal closed packed structure are:-
The packing efficiency of the two dimensional square unit cell shown below is:
A compound forms hexagonal close-packed structure. What is the total number of voids in 0.5 mol of it? How many of these are tetrahedral voids?
Which of the following is frenkal effect.
The number of tetrahedral and octahedral voids in a CCP array of 100 atoms are respectively:
The right option for the number of tetrahedral and octahedral voids in the hexagonal primitive unit cell is ______.
The right option for the number of tetrahedral and octahedral voids in hexagonal primitive unit cell is ______.
Ionic radii of cation A+ and anion B- are 102 and 181 pm respectively. These ions are allowed to crystallize into an ionic solid. This crystal has cubic close packing for B-. A+ is present in all octahedral voids. The edge length of the unit cell of the crystal AB is ______ pm. (Nearest integer)
