which of the following has lowest melting point?
CaCl2, CaBr2, CaI2, CaF2
CaBr2 has the lowest melting point.
In case of Covalent halides generally the trend in melting point of compound is as follows :
Fluoride < Chloride < Bromide < Iodide
This trend is observed because of the increasing vanderwaal forces with increase in size of the halide ion in covalent halide.
In case of Ionic halides the trend is reversed as the major governing factor is the lattice energy.
Fluoride > Chloride > Bromide > Iodide
But as in the case of Calcium halides the first three halides are ionic ,calcium chloride being partially ionic and partially covalent but the last Calcium Iodide is purely covalent the trend is
CaF2 > CaCl2 > CaBr2 < CaI2
1360 oC 772 oC 730 oC 740 oC
In case of Covalent halides generally the trend in melting point of compound is as follows :
Fluoride < Chloride < Bromide < Iodide
This trend is observed because of the increasing vanderwaal forces with increase in size of the halide ion in covalent halide.
In case of Ionic halides the trend is reversed as the major governing factor is the lattice energy.
Fluoride > Chloride > Bromide > Iodide
But as in the case of Calcium halides the first three halides are ionic ,calcium chloride being partially ionic and partially covalent but the last Calcium Iodide is purely covalent the trend is
CaF2 > CaCl2 > CaBr2 < CaI2
1360 oC 772 oC 730 oC 740 oC