Molecular shape trigonal planar

Look again at Table 9-3 on the previous page. Notice that the number of atomic orbitals mixed to form the hybrid orbital equals the total number of pairs of electrons. In addition, the number of hybrid orbitals formed equals the number of atomic orbitals mixed. For example, AICI3 has a total of three pairs of electrons and VSEPR predicts a trigonal planar molecular shape. To have this shape, one s and two p orbitals on the central atom A1 must mix to form three identical sp hybrid orbitals. 

B Methane has a molecular geometry that is tetrahedral, while BF3 is trigonal planar in shape and XeF6 is octahedral in shape. 

This molecule is of the type AX2E it has a trigonal planar electron-group geometry and a bent molecular shape. 

We also need to be able to deal with the effect of unpaired electrons. Radicals such as N02 have a single nonbonding electron. Such an electron is a region of high electron density and is treated like a lone pair when determining molecular shape. Thus, N02 (20) has a trigonal planar... 

Find a flowering plant that interests you. Look at the root formation, leaf shapes and how they are attached to the stem, and the shape of the flower. Draw these different shapes. Find molecules that resemble these different shapes. Remember that group 3A elements form trigonal planar shaped molecules, group 4A elements form tetrahedral shaped molecules, group 5A elements form pyramid shaped molecules and group 6A elements form bent shaped molecules. Carbon chains have a zigzag shape and the DNA molecule is a double helix. You will see that these molecular shapes are duplicated in natural objects. See how many molecular shapes you can find in an ordinary flower. 

To determine the molecular structure, we must count the electron pairs around the sulfur atom. In each resonance structure the sulfur has one lone pair, one pair in a single bond, and one double bond. Counting the double bond as one pair yields three effective pairs around the sulfur. According to Table 13.8, a trigonal planar arrangement is required, yielding a V-shaped molecule ... 

Notice the three single bonds around the central boron atom. Like three spokes of a wheel, these shared pairs of electrons extend from the central boron atom. The three F atoms, each of which has three unshared pairs, will repel each other and will be at a maximum distance apart. This molecular shape is known as trigonal planar, as shown in Figure 16. 

Molecular shapes predicted by VSEPR theory include linear, bent, trigonal planar, tetrahedral, and trigonal pyramidal. 

Molecular shape Tetrahedral at methyl carbon atom, trigonal planar at aldehyde C atom... 

The molecular shape is trigonal planar and it is a non-polar molecule. It can not participate dipole-dipole interactions. 

Molecular Shapes with Three Electron Groups (Trigonal Planar Arrangement)... 

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° ... 

Step 4. Draw and name the molecular shape With three electron groups and no lone pairs, COCI2 has a trigonal planar shape (AX3) ... 

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