<p>Molecular size of ICI and&nbsp;<math xmlns="http://www.w3.org/1998/Math/MathML"><mi>B</mi><msub><mi>r</mi><mn>2</mn></msub></math>&nbsp; is nearly same, but boiling point of ICI is about&nbsp;<math xmlns="http://www.w3.org/1998/Math/MathML" class="wrs_chemistry"><msup><mn>40</mn><mo>&#176;</mo></msup><mi mathvariant="normal">C</mi></math>&nbsp;higher than&nbsp;<math xmlns="http://www.w3.org/1998/Math/MathML"><mi>B</mi><msub><mi>r</mi><mn>2</mn></msub></math>. This might be due to:</p>