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Si + 3 HCl → HSiCl 3 + H 2. The trichlorosilane is then converted to a mixture of silane and silicon tetrachloride: 4 HSiCl 3 → SiH 4 + 3 SiCl 4. This redistribution reaction requires a catalyst. The most commonly used catalysts for this process are metal halides, particularly aluminium chloride. This is referred to as a redistribution ...
disilane, Si 2 H 6 or H 3 Si−SiH 3, 2 silicon atoms and 6 hydrogen atoms, analogous to ethane; trisilane, Si 3 H 8 or H 2 Si(−SiH 3) 2, 3 silicon atoms and 8 hydrogen atoms, analogous to propane; tetrasilane, Si 4 H 10 or H 3 Si−SiH 2 −SiH 2 −SiH 3, 4 silicon atoms and 10 hydrogen atoms, analogous to butane (one isomer: isotetrasilane ...
This shape is found when there are four bonds all on one central atom, with no extra unshared electron pairs. In accordance with the VSEPR (valence-shell electron pair repulsion theory), the bond angles between the electron bonds are arccos(− 1 / 3 ) = 109.47°. For example, methane (CH 4) is a tetrahedral molecule.
Valence shell electron pair repulsion (VSEPR) theory (/ ˈ v ɛ s p ər, v ə ˈ s ɛ p ər / VESP-ər, [1]: 410 və-SEP-ər [2]) is a model used in chemistry to predict the geometry of individual molecules from the number of electron pairs surrounding their central atoms. [3]
In the natural bond orbital viewpoint of 3c–4e bonding, the triiodide anion is constructed from the combination of the diiodine (I 2) σ molecular orbitals and an iodide (I −) lone pair. The I − lone pair acts as a 2-electron donor, while the I 2 σ* antibonding orbital acts as a 2-electron acceptor. [12]
[11] [12] This electron distance maximization happens to achieve the most stable electron distribution. [11] [12] The result of VSEPR theory is being able to predict bond angles with accuracy. According to VSEPR theory, the geometry of a molecule can be predicted by counting how many electron pairs and atoms are connected to a central atom.
This would result in the geometry of a regular tetrahedron with each bond angle equal to arccos(− 1 / 3 ) ≈ 109.5°. However, the three hydrogen atoms are repelled by the electron lone pair in a way that the geometry is distorted to a trigonal pyramid (regular 3-sided pyramid) with bond angles of 107°.
Gilbert N. Lewis introduced the concepts of both the electron pair and the covalent bond in a landmark paper he published in 1916. [1] [2] MO diagrams depicting covalent (left) and polar covalent (right) bonding in a diatomic molecule. In both cases a bond is created by the formation of an electron pair.