Boron trifluoride bond angles

Boron trifluoride is a trigonal planar molecule There are six electrons two for each B—F bond associated with the valence shell of boron These three bonded pairs are farthest apart when they are coplanar with F—B—F bond angles of 120°... 

Now consider boron trifluoride, BF3 in which boron is covalently bonded to three fluorine atoms. For the electron pairs to remain as far apart as possible, the arrangement is triangular with a 120° angle between fluorines ... 

Figure 6.24 illustrates a similar situation in boron trifluoride, BF3, where three fluorine atoms are oriented 120° from one another around a central boron atom. Because the angles are all the same, and because each fluorine atom pulls on the electrons of its boron—fluorine bond with the same force, the resulting polarity of this molecule is zero. 

SAMPLE SOLUTION (a) Boron trifluoride is planar with 120° bond angles. Although each boron-fluorine bond is polar, their combined effects cancel and the molecule has no dipole moment. 

A boron trifluoride molecule, BF3, has the Lewis structure shown in (5). There are three bonding pairs attached to the central atom and no lone pairs. According to the VSEPR model, as illustrated in Fig. 3.4, the three bonding pairs, and the fluorine atoms they link, lie at the corners of an equilateral triangle. Such a structure is trigonal planar, and all three F—B—F angles are 120° (6). 

FIGURE 1.10 Representations of the trigonal planar geometry of boron trifluoride (BF3). There are 6 electrons in the valence shell of boron, a pair for each covalent bond to fluorine. The three pairs of electrons are farthest apart when the F — B—F angle is 120°. 

When the three electron groups are bonding groups, the molecular shape is trigonal planar (AX3). Boron trifluoride (BF3), another electron-deficient molecule, is an example. It has six electrons around the central B atom in three single bonds to F atoms. The nuclei lie in a plane, and each F—B—F angle is 120° ... 

What is the geometric structure of the boron trifluoride molecule, BF3 How many pairs of valence electrons are present on the boron atom in BF3 What are the approximate F—B—F bond angles in BF3 ... 

PRACTICE PROBLEM 1.25 What do the bond angles of boron trifluoride surest about the hybridization state of... 

The shape of boron trifluoride molecule is planar triangle with bond angles 120°. VSEPR theory predicts sp hybridization of boron atom and a planar triangle shape. 

Boron trifluoride has a trigonal-planar structure, with all F——F bond angles 120°. Boron has Is and 2 orbitals that bond with the fluorine Is and Ip orbitals. A convenient coordinate system for a discussion of bonding in BFj is shown in Fig. 4-1. 

Boron is an element in group 13 of the periodic table. Therefore, it has three valence electrons. The Lewis structure (Figure 4-45) of the boron trifluoride molecule, BF3, shows there are only three electron pairs (three electron domains) in the valence shell of the boron atom. These three bonding pairs repel each other equally, with the result that the boron trifluoride molecule is a trigonal planar (flat) molecule. The three boron-fluorine bonds point towards the three corners of an equilateral triangle. The bond angles are all equal at 120°. 

Further evidence supporting this conclusion comes from comparing the bond angles in boron trifluoride and formaldehyde ... 

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