Analysis shows that an oxide ore of nickel has formula Ni0.98O1.00. The percentage of nickel as Ni3+ ions is nearly


Correct option is



Let the number of nickel ions = 98

∴ the number of oxide ions = 100

Total negative charge on O2- ions = 2 × 100 = 200

 Let number of  Ni3+ ions = x  

∴ Number of Ni2+ ions = 98 – x

x × 3 + (98 - x) × 2 = 200

                             x = 4

% of Ni as Ni3+ =  × 100 = 4.08%




The crystal system of a compound with unit cell dimensions,

a = 0.387, b = 0.387 and c = 0.504 nm, and α = β = 900 and γ = 1200 is


If Z is the number of atoms in the unit cell that represents the closest packing sequence …… ABC ABC …… the number of tetrahedral voids in the unit cell is equal to


In which of the following crystals alternate tetrahedral voids are occupied?


A solid is made of two elements X and Z. the atoms Z are in ccp arrangement while the atom X occupy all the tetrahedral sites. What is the formula of the compound?


An element occurring in the bcc structure has 12.08 × 1023 unit cells. The total number of atoms of the elements in these cells will be


The number of sphere contained (i) in one body centred cubic unit cell and (ii) in one face centred cubic unit cell, is


CsBr crystal has bcc structure. It has an edge length of 4.3. the shortest interionic distance between Cs+ and Br –  ions is



The number of atoms in 100 g of an fcc crystal with density,

d = 10g/ cm3 and cell edge equal to 100 pm, is equal to


The number of unit cell in 58.5 g of NaCl is nearly


In orthorhombic, the value of a, b and c are respectively 4.2, 8.6 and8.3. given the molecular mass of the solute is 155 g mol-1 and that of density is 3.3 g/cc, the number of formula units per unit cell is