-2
$\begingroup$

why are some semimetals considered as a metal, and some, a nonmetal when paired with some atoms. Like in BF, it is an ionic bond, but in SiCl, it is a covalent bond. Do their electronegativities matter?

Improve this question
$\endgroup$
1
  • 2
    $\begingroup$ I would never call a $\ce{B-F}$ bond ionic. $\endgroup$ – Ivan Neretin Feb 18 '16 at 14:24
1
$\begingroup$

Yes, in fact difference in electronegativity is the defining property. Ionic character of a bond is given by: $$ \mathrm{\% IC = 1-exp[-\frac{1}{4}(\chi_A - \chi_B)^2]}$$ Where $\chi_A$ and $\chi_B$ are the electronegativities of the anion and cation species. When $|\chi_A - \chi_B|$ exceeds 1.665 the ionic character transitions from less than $50\%$ ionic to more than $50\%$ ionic, making the compound ionic.

Improve this answer
$\endgroup$
3
  • $\begingroup$ oh so, if i subtract the electronegativity of a, for example, a semimetal and a nonmetal, and if it is greater than 1, will the semimetal become a metal? $\endgroup$ – user26957 Feb 18 '16 at 14:23
  • $\begingroup$ No, not at all. Electronegativity is only informative about the ionic nature of the bond. $\endgroup$ – A.K. Feb 18 '16 at 14:57
  • $\begingroup$ It's only a suggestion about nature of bonding chemistry.stackexchange.com/questions/17064/… $\endgroup$ – Mithoron Feb 18 '16 at 16:50

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.