Coordination Number

Q. Which of the following is correct for a 3-D hexagonal closed packing lattice ?
Here
\(Z_{eff}=\text{Total number of atoms in hcp lattice}\\O_v=\text{Total number of octahedral voids}\\T_v=\text{Total number of tetrahedral voids}\)

Q. What is the coordination number of hexagonal close packing (hcp) lattice?

1. 8
2. 4
3. 6
4. 12

Q. The $C{l}^{-}$ ions in the of NaCl lattice structure are present at:

Q. The ionic radii of $A^{+}$ and $B^{-}$ ions are $0.98\times {10}^{-10}m$ and $1.81\times {10}^{-10}m$. The coordination number of each ion in AB is:
(NEET 2016)

Q. A solid $‘A{B}^{\prime }$ has the $NaCl$ structure, and $‘A^{\prime }$ atoms occupy the corners of the cubic unit cell. If all the face-centred atoms along one of the axes are removed, then the resultant formula of the of the unit cell of the solid will be:

1. $A{B}_2$
2. $A_{2}B$
3. $A_3{B}_4$
4. $A_4{B}_3$

Q. Which of the following is correct for a 3-D hexagonal closed packing lattice ?
Here
$Z_{eff}=\text{Total number of atoms in hcp lattice}{O}_v=\text{Total number of octahedral voids}{T}_v=\text{Total number of tetrahedral voids}$

1. $\frac{O_v}{Z_{eff}}=1.5$
2. $\frac{O_v}{Z_{eff}}=0.25$
3. $\frac{T_v}{Z_{eff}}=0.5$
4. $\frac{T_v}{Z_{eff}}=2$

Q. The $C{l}^{-}$ ions in the of NaCl lattice structure are present at:

1. Edge centres of the cube
2. Corners as well as face centres of the cube
3. Centres of faces of the cube
4. Corners of the cube

Q.

In H.C.P. arrangement in three dimensions, the overall coordination number of each sphere is

1. 4

2. 6

3. 9

4. 12

Q.

Potassium crystallizes in a bcc lattice, hence the coordination number of potassium in potassium metal is

[KCEE 1993]

1. 0

2. 4

3. 6

4. 8

Q. A solid $‘A{B}^{\prime }$ has the $NaCl$ structure, and $‘A^{\prime }$ atoms occupy the corners of the cubic unit cell. If all the face-centred atoms along one of the axes are removed, then the resultant formula of the of the unit cell of the solid will be:

1. $A{B}_2$
2. $A_{2}B$
3. $A_3{B}_4$
4. $A_4{B}_3$

Q. Which of the following have coordination number 4:8?

1. ${\mathrm{Li}}_{2}O$
2. ${\mathrm{BaCl}}_2$
3. ${\mathrm{Rb}}_{2}O$
4. $K_{2}O$

Q. Consider a cube with atom 'M' occupying the body centre, atom 'A' occupying the corners of the cube, atom 'B' occupying the edges of the cube and atom 'C' occupying the face centres.
Mark the correct options when the formula is $M_m{A}_a{B}_b{C}_c$, if:

1. Plane is drawn diagonally, atoms in the plane vanish, ratio of $c:a$ is 4
2. Plane is drawn diagonally, atoms in the plane vanish, $a+b=8$
3. Line is drawn along an edge, atoms on the line vanish, $a+b=14$
4. Line is drawn along an edge, atoms on the line vanish, ratio of $c:a$ is 4

Q. For some crystals, the radius ratio for cation and anion is 0.525, its coordination number will be

1. 2

2. 4

3. 6

4. 8

Q. A certain solid has a structure in which $X$ atoms are located at the corners of the cubic cell, $O$ at the edge centres and $Y$ at the body centres. Then the formula of the cell is $X_a{Y}_b{O}_c$.
If $O$ atoms are missing from any two edge centres per unit cell, the formula is $X_x{Y}_y{O}_z$.
Find the value of $(a+b+c)+(x+y+z)$.

Q. In Calcium fluoride, having the fluorite structure, the coordination numbers for calcium ion $\left(C{a}^{2+}\right)$ and fluoride ion $\left(F^{-}\right)$ are

1. 8 and 4
2. 4 and 8
3. 4 and 2
4. 6 and 6