eng Ansari Education and Research Society Journal of Ultra Scientist of Physical Sciences April 2010 22 1 53 62 juc 897 article DHEERENDRA SINGH YADAV (dherendra0000@gmail.com) 1 Department of Physics, Agra College, Agra - 282002, UTAR PRADESH -INDIA <p style="text-align: justify;">The electronic properties <em>viz.</em> bond ionicity and heat of formation of A^IB^IIIC₂^VIternary semiconductor compounds with chalcopyrite structure are investigated using Phillips and Van-Vechten&#39;s dielectric theory^27-29 of solids. The values of homopolar energy gap, heteropolar energy gap and average energy gap have been evaluated for these materials. Using these parameters, Phillips ionicity of the bonds <em>AC</em> and <em>BC</em> is evaluated and is used to determine the heat of formation (-D<em>H_f</em>) for these materials. The presently investigated values of (-D<em>H_f</em>) are found in good agreement with the experimental data and reported literature values.<br /> &nbsp;</p> https://ultraphysicalsciences.org/paper/897/ Bond ionicity Heat of formation