Question

‘The chemistry of beryllium is not essentially ionic.’ Justify the statement by making a reference to the nature of oxide, chloride and fluoride of beryllium.

Answer 1

    Ionic radius of Beryllium is very small hence it have high polarizing power. When compared to the remaining elements of same group elements, it has very high polarizing power.

       For this reason, the compounds of beryllium are essentially covalent in nature. In fact beryllium salts are soluble in organic solvents and sparingly soluble in water. The melting point and boiling point of the beryllium little bit low than remaining alkaline earth metals.

      Beryllium oxides are react with both acids and alkalis therefore its oxides are amphoteric in nature.  The remaining group 2 metal oxides are more ionic.

       The following chemical reactions of beryllium shows heir hygroscopic nature.

$Be{ F }_{ 2 }(s)\quad +\quad 4{ H }_{ 2 }O\quad (l)\quad \rightarrow \quad [Be({ H }_{ 2 }O{ ) }_{ 4 }]F_{ 2 }(s)\\ Be{ Cl }_{ 2 }(s)\quad +\quad 4{ H }_{ 2 }O\quad (l)\quad \rightarrow \quad [Be({ H }_{ 2 }O{ ) }_{ 4 }]Cl_{ 2 }(s)$

       Halides of beryllium like beryllium fluoride and beryllium chloride are covalent and polymeric. And these are sublime and do not conduct electricity. All the above properties clearly show the covalent nature of the halides.