In calcium fluoride, having the fluorite structure, the coordination numbers for calcium ion $(Ca^{2+})$ and fluoride ion $(F^-)$ are
- 4 and 2
- 6 and 6
- 8 and 4
- 4 and 8
The Correct Option is C
Solution and Explanation
Calcium Fluoride Crystal Structure
Calcium fluoride crystallizes in a Face-Centered Cubic (FCC) unit cell with an edge length of \(5.463\) Angstroms. The unit cell structure consists of:
- Calcium cations (\(Ca^{2+}\)) in blue, which occupy the FCC lattice sites.
- Fluoride anions (\(F^{-}\)) in green, occupying all tetrahedral sites.
The fluoride anions are surrounded by 4 calcium cations, which are arranged at the vertices of a tetrahedron, creating a tetrahedral coordination geometry. The calcium cations have 8 fluoride anions as neighbors, arranged at the corners of a smaller cube.
The \(Ca: F\) coordination ratio is \(8: 4\) or \(2: 1\), meaning for every two calcium cations, there is one fluoride anion.
In \(CaF_{2}\), the coordination number of \(Ca^{+2}\) is 8, as each calcium ion is surrounded by 8 fluoride ions in the structure.
Top Questions on The solid state
- How many kinds of Bravais lattice are possible in a crystal?
- Bihar Board XII - 2025
- Chemistry
- The solid state
- The percentage of free space in a body-centred cubic unit cell is
- Bihar Board XII - 2025
- Chemistry
- The solid state
- The number of atoms present in body-centred cubic unit cell is
- Bihar Board XII - 2025
- Chemistry
- The solid state
- Which of the following is not a crystalline solid?
- Bihar Board XII - 2025
- Chemistry
- The solid state
- A metal crystallizes in simple cubic lattice. The volume of one unit cell is \( 6.4 \times 10^{-7} \, \text{pm}^3 \). What is the radius of the metal atom in pm?
- AP EAPCET - 2025
- Chemistry
- The solid state
Questions Asked in NEET exam
- Which of the following organisms cannot fix nitrogen? A. Azotobacter
B. Oscillatoria
C. Anabaena
D. Volvox
E. Nostoc
Choose the correct answer from the options given below:- NEET (UG) - 2025
- Nitrogen Fixation
- Which of the following are paramagnetic?
A. [NiCl$_4$]$^{2-}$
B. Ni(CO)$_4$
C. [Ni(CN)$_4$]$^{2-}$
D. [Ni(H$_2$O)$_6$]$^{2+}$
E. Ni(PPh$_3$)$_4$
Choose the correct answer from the options given below:- NEET (UG) - 2025
- Coordination chemistry
Given below are two statements: One is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A): A typical unfertilized, angiosperm embryo sac at maturity is 8-nucleate and 7-celled.
Reason (R): The egg apparatus has 2 polar nuclei.In the light of the above statements, choose the correct answer from the options given below:
- NEET (UG) - 2025
- Angiosperms
- A ball of mass 0.5 kg is dropped from a height of 10 m. The ball hits the ground and rises to a height of 1.5 m. The impulse imparted to the ball during its collision with the ground is : (Take \(g = 9.8 \, \text{m/s}^2\))
- NEET (UG) - 2025
- Collision and Impulse
- Consider the diameter of a spherical object being measured with the help of a Vernier Callipers. Suppose its 10 Vernier Scale Divisions (V.S.D.) are equal to its 9 Main Scale Divisions (M.S.D.). The least count in the M.S. is 0.1 cm and the zero of V.S. is at -0.1 cm when the jaws of Vernier callipers are closed. If the main scale reading for the diameter is \(M = 5\) cm and the number of coinciding vernier division is 8, the measured diameter after zero error correction, is:
- NEET (UG) - 2025
- Measurement of length
Concepts Used:
Solid State
Solids are substances that are featured by a definite shape, volume, and high density. In the solid-state, the composed particles are arranged in several manners. Solid-state, in simple terms, means "no moving parts." Thus solid-state electronic devices are the ones inclusive of solid components that don’t change their position. Solid is a state of matter where the composed particles are arranged close to each other. The composed particles can be either atoms, molecules, or ions.
Types of Solids:
Based on the nature of the order that is present in the arrangement of their constituent particles solids can be divided into two types;
- Amorphous solids behave the same as super cool liquids due to the arrangement of constituent particles in short-range order. They are isotropic and have a broad melting point (range is about greater than 5°C).
- Crystalline solids have a fixed shape and the constituent particles are arranged in a long-range order.