CHEM101 Lecture : Chem 101 Lecture October 9.docx

• School: University of Alberta
• Department: Chemistry
• Course: CHEM101
• Professor: Yoram Apelblat

Document Summary

Electron deficient compounds: be, b and al often have less than 8 electrons i. e. : bf3, valence electrons: 3 + 3(7) = 24, fluorine is always terminal, boron is central, 24 total 6 bonded = 18 to distribute, all will be distributed to fluorine atoms leaving boron with only 6, fc f = 7 (6+ 2) = 0, fc b = 3 (0 + 6) = 0, even though boron only has 6 electrons, fc is minimized therefore this is acceptable, tend to be reactive, boron will try to obtain 2 more electrons if possible i. e. : bf3 + nh3 where ammonia has one lone pair, reaction will occur resulting in complex of the combined compounds, bf3 is said to be lewis acid because it accepts electron pair, nh3 is said to be lewis base because it donates electron pair.