Advertisements
Advertisements
Question
An ionic compound crystallises in FCC type structure with ‘A’ ions at the centre of each face and ‘B’ ions occupying corners of the cube. The formula of compound is _______.
Options
AB4
A3B
AB
AB3
Advertisements
Solution
'A' ions are at the centre of each face. There are six face centres and each contributes one half to the unit cell. Total number of A ions present per unit cell
`=6 xx 1/2 = 3`.
'B' ions occupy corners of the cube. There are 8 corners and each contributes one eight to the unit cell.
Total number of B ions present per unit cell
`=8xx1/8=1`.
The formula of a compound is A3B
Hence, the correct answer is A3B.
APPEARS IN
RELATED QUESTIONS
Ionic solids conduct electricity in molten state but not in solid state. Explain
Copper crystallises into a fcc lattice with edge length 3.61 × 10−8 cm. Show that the calculated density is in agreement with its measured value of 8.92 g cm−3.
Distinguish between crystalline solids and amorsphous solids.
How are the crystalline solids classified?
Solid CO2 is an example of ____________.
Assertion: monoclinic sulphur is an example of a monoclinic crystal system
Reason: for a monoclinic system, a ≠ b ≠ c and α = γ = 90°, β ≠ 90°
Give any three characteristics of ionic crystals.
Classify the following solid.
Brass
Dry ice is an example of ____________.
Which among the following is NOT a polar molecular solid?
Brass is an example of ____________.
Solid X is a very hard electrical insulator in solid as well as in molten state. It melts at extremely high temperature. Solid X is a ____________.
Order of increasing melting points among H2O(s), C(s), CS2 and Sn is ____________.
Silicon carbide is an example of ____________.
London forces are present in ____________.
MgO has the structure of NaCl. The coordination number of the ions in MgO is ____________.
Which of the following exists as covalent crystals in the solid state?
Which of the following is not the characteristic of ionic solids?
Which of the following cannot be regarded as molecular solid?
(i) SiC (Silicon carbide)
(ii) AlN
(iii) Diamond
(iv) I2
Which of the following is not true about the ionic solids?
Why are liquids and gases categorised as fluids?
Who introduced the term covalent bond?
Calculate the angle at which first order reflection will occurs in an X-ray spectrometer when x ~ rays of wavelength \[\ce{1.54 \overset{\circ}{A}}\] are diffracted by the atoms of a crystal given that inter planer distance is \[\ce{0.04 \overset{\circ}{A}}\]
Which of the following molecules is non-polar in nature?
Which of the following is not correct?
Mention the res of the following solid:
Ice
Quartz is which type of crystal?
