What is the molecular geometry of PBr5? Draw its VSEPR and Lewis structure.

1 Answer
Jan 1, 2015

#PBr_5#'s molecular geometry is trigonal bipyramidal.

Let's start with its Lewis structure. #P# has 5 valence electrons and #Br# has 7 valence electrons, which means that a total of #5 + 5*7 = 40# electrons must be accounted for.

http://www.chem.purdue.edu/vsepr/prelab_answers.html

#P#'s bonds with the five #Br# atoms account for #5 * 2 = 10# electrons, while the three lone pairs on each #Br# atom complete the rest of the electrons - #5 * 6 =30# electrons.

SInce #P# forms bonds with 5 other atoms and has no lone pairs, it has a steric number and a coordination number equal to 5 . According to VSEPR Theory, this corresponds to a trigonal bipyramidal molecular geometry.

http://chemistry.stackexchange.com/questions/16992/asymmetry-in-trigonal-bipyramidal-geometry