Tetrahedral electron-group geometry

An inner atom with a steric number of 4 has tetrahedral electron group geometry. 

A steric number of 4 identifies four electron groups that must be separated in three-dimensional space. Four groups are as far apart as possible in tetrahedral electron group geometry. 

Both atoms have tetrahedral electron group geometry. 

Many elements of the periodic table, from titanium and tin to carbon and chlorine, exhibit tetrahedral electron group geometry and tetrahedral molecular shapes. In particular, silicon displays tetrahedral shapes in virtually all of its stable compounds. 

Quartz, a common form of silica, is a network of Si—O bonds. Silicon and oxygen both have tetrahedral electron group geometry. All the silicon atoms have tetrahedral shapes and all the oxygen atoms have bent shapes. 

According to the VSEPR model developed in Chapter 9, an inner atom with a steric number of 4 adopts tetrahedral electron group geometry. This tetrahedral arrangement of four electron groups is very common, the only important exceptions being the hydrides of elements beyond the second row, such as H2 S and PH3. Thus,... 

Both inner atoms have steric numbers of 4 and tetrahedral electron group geometry, so both can be described using s p hybrid orbitals. All four hydrogen atoms occupy outer positions, and these form bonds to the inner atoms through 1 s-s p overlap. The oxygen atom has two lone pairs, one in each of the two hybrid orbitals not used to form O—H bonds. 

The Lewis structure of NC13 has three Cl atoms bonded to N and one lone pair attached N. These four electron groups around N produce a tetrahedral electron-group geometry. The fact that one of the electron groups is a lone pair means that the molecular geometry trigonal pyramidal. 

B The Lewis structure of POCl3 has three single P-Cl bonds and one P-0 bond. These four electron groups around P produce a tetrahedral electron-group geometry. No lone pairs are attached to P and thus the molecular geometry is tetrahedral. 

This molecule is of the type AX3E it has a tetrahedral electron-group geometry and a trigonal pyramidal molecular shape. 

In BF4", there are a total of 1 + 3 + (4 x 7) = 32 valence electrons, or 16 electron pairs. A plausible Lewis structure has B as the central atom. This ion is of the type AX4 it has a tetrahedral electron-group geometry and a tetrahedral shape. 

C1F2] After the removal of one F during the reaction, the central Cl atom is now surrounded by four electron pairs two bonding and two lone electron pairs. This results in a tetrahedral electron group geometry and a bent molecular shape. 

The NHj molecule has a tetrahedral electron-group geometry with three bonded atoms, which gives it a trigonal pyramidal shape. Thus, a NH3 molecule is polar because the individual N—H dipoles do not cancel. 

Molecular shapes based on tetrahedral electron-group geometry of CH4, NH3, and H2O... 

H — S — H, VSEPR theory predicts a tetrahedral electron-group geometry, which in turn suggests a tetrahedral bond angle—that is, 109.5°. However, by modifying this initial VSEPR prediction to accommodate lone-pair-lone-pair and lone-pair-bond-pair repulsions (see page 443), the predicted bond angle is less than 109.5°. 

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