The observed angle of 104.5° is experimental evidence for which quantum-mechanical calculations give a useful explanation: Valence bond theory must include a hybridization component to give accurate predictions. Consequently, the overlap of the O and H orbitals should result in a tetrahedral bond angle (109.5°). The valence orbitals in an oxygen atom in a water molecule differ they consist of four equivalent hybrid orbitals that point approximately toward the corners of a tetrahedron ( ).

The valence orbitals in an isolated oxygen atom are a 2 s orbital and three 2 p orbitals. The new orbitals that result are called hybrid orbitals. This process of combining the wave functions for atomic orbitals is called hybridization and is mathematically accomplished by the linear combination of atomic orbitals, LCAO, (a technique that we will encounter again later). When atoms are bound together in a molecule, the wave functions combine to produce new mathematical descriptions that have different shapes. The mathematical expression known as the wave function, ψ, contains information about each orbital and the wavelike properties of electrons in an isolated atom. Quantum-mechanical calculations suggest why the observed bond angles in H 2O differ from those predicted by the overlap of the 1 s orbital of the hydrogen atoms with the 2 p orbitals of the oxygen atom. This is not consistent with experimental evidence. The hypothetical overlap of two of the 2 p orbitals on an oxygen atom (red) with the 1 s orbitals of two hydrogen atoms (blue) would produce a bond angle of 90°. The prediction of the valence bond theory model does not match the real-world observations of a water molecule a different model is needed. Experimental evidence shows that the bond angle is 104.5°, not 90°. If this were the case, the bond angle would be 90°, as shown in, because p orbitals are perpendicular to each other. Valence bond theory would predict that the two O–H bonds form from the overlap of these two 2 p orbitals with the 1 s orbitals of the hydrogen atoms.

Oxygen has the electron configuration 1 s 22 s 22 p 4, with two unpaired electrons (one in each of the two 2 p orbitals). As an example, let us consider the water molecule, in which we have one oxygen atom bonding to two hydrogen atoms. However, to understand how molecules with more than two atoms form stable bonds, we require a more detailed model. Thinking in terms of overlapping atomic orbitals is one way for us to explain how chemical bonds form in diatomic molecules. Determine the hybrid orbitals associated with various molecular geometries.Explain the concept of atomic orbital hybridization.Spectroscopic and Magnetic Properties of Coordination CompoundsĪldehydes, Ketones, Carboxylic Acids, and Estersīy the end of this section, you will be able to: Occurrence, Preparation, and Properties of Transition Metals and Their CompoundsĬoordination Chemistry of Transition Metals Transition Metals and Coordination Chemistry Occurrence, Preparation, and Properties of the Noble Gases Occurrence, Preparation, and Properties of Halogens Occurrence, Preparation, and Properties of Sulfur Occurrence, Preparation, and Compounds of Oxygen Occurrence, Preparation, and Properties of Phosphorus Occurrence, Preparation, and Properties of Nitrogen Occurrence, Preparation, and Properties of Carbonates Occurrence, Preparation, and Compounds of Hydrogen Structure and General Properties of the Nonmetals Structure and General Properties of the Metalloids Occurrence and Preparation of the Representative Metals Representative Metals, Metalloids, and Nonmetals The Second and Third Laws of Thermodynamics Shifting Equilibria: Le Châtelier’s Principle Stoichiometry of Gaseous Substances, Mixtures, and Reactions Relating Pressure, Volume, Amount, and Temperature: The Ideal Gas Law Periodic Variations in Element Properties Mathematical Treatment of Measurement Resultsĭetermining Empirical and Molecular FormulasĮlectronic Structure and Periodic Properties of ElementsĮlectronic Structure of Atoms (Electron Configurations) Measurement Uncertainty, Accuracy, and Precision

Hydronium ion bonding and hybridization