The Solid State

  • Question 29

    A cubic solid is made of two elements Y and Z. Atoms of Z are at the corners of the cube and Y at the body centre. What is the formula of the compound?


    Number of Z per unit cell = 1/8 x 8Z = 1 Z.
    Number of X per unit cell = 1 Y.
    Formula of the compound = ZY.

    Question 30

    MgO has rock salt type structure. What is the co-ordination number of each ion?

    The co-ordination number of each ion in MgO is six.
    Question 31

    Thallium chloride exists in Cs CI type lattice. What are the co-ordination number of TI and Cl ions?

    The co-ordination number of each ion is 8. Thallium chloride is a 8:8 co-ordination lattice.
    Question 32

    What is the effect of pressure on NaCl type crystals?

    High pressure increases the co-ordination number from 6:6 to 8:8.

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