Answer to Question #112292 in Chemistry for TM

Question

Hi,please help with this question.I am struggling to identify the molecular geometry of SnCl3-
Thank you

Answer 1

Let's consider the electronic structure of SnCl₃^-. Sn has 4 electrons in its valence shell: 5s²5p². Sn forms 3 bonds with chlorine atoms, sharing three electrons (lines in figure below). The electron left in its valence shell and the extra electron that comes from the negative charge form a nonbonding electron pair. Therefore, the SnCl₃^- ion corresponds to the generic formula AX₃E in VSEPR theory, where A is the central atom (Sn), X is the atom bonded to the central atom (Cl) and E is the lone pair. According to this notation, SnCl₃^- electron pair geometry is tetrahedral, and its molecular geometry is trigonal pyramidal: