Name: covalent bond overlap and orbital hybridization
Uploaded: 2025-05-22T09:05:33.000Z
Duration: 2 min 38 s
Channel: JoVE

Valence 채권 이론은 화학 결합이 부분적으로 채워진 원자 궤도의 중복을 통해 결과 제안, 구형 의 궤도 이외의 것을 포함.
두 개의 비구형 궤도 사이에 하나의 결합이 형성되면 두 궤도는 정면으로 겹칩니다.
원자 궤도의 일대일 오버랩에 의해 형성 된 공유 결합의 유형은 시그마 결합이라고합니다.
s와 p 궤도가 겹쳐서 공유 결합을 형성하도록 하는 것은 VSEPR 모델에서 다양한 분자 형상을 산출할 수 없다. Valence 결합 이론은 원자 궤도의 혼성화, 또는 혼합을 통해 이 분자 기하학을 설명하는 데 도움이 됩니다.
결합에 관여하는 일부 원자 궤도는 형상이 원본의 하이브리드인 새로운 궤도를 형성하기 위해 재결합합니다. 원자 궤도의 초기 수와 생성된 하이브리드 궤도의 수는 항상 동일합니다.
하이브리드 궤도는 구성 원자 궤도와 다른 형태를 가지며, 한 엽은 다른 것보다 훨씬 큽니다. 따라서, 전자 확률 밀도는 다른 원자의 궤도와 보다 효과적인 중첩을 초래하는 방향 엽에 고도로 집중된다. 명확성을 위해, 이 궤도는 수시로 작은 엽 없이 표시됩니다.
예를 들어, 탄소의 흥분 상태에서, 네 개의 짝을 이루는 전자를 포함하는 1 s와 3 개의 p 궤도는 혼성화를 거치며, 일반 테트라헤드론의 정점을 차지하는p-3궤도 - 4 개의 동등한 하이브리드 s를산출합니다.
탄소의 흥분 상태에서 하나의 s와 두 개의 p 궤도의 혼합은 세 개의 동등한 s를생성 -삼각평면 형상p-2 하이브리드 궤도.
마찬가지로, 1s와 1p 궤도의 혼성화는 서로 180도에서 두 개의 스프 궤도를 만들 수 있습니다.
혼성화의 개념은 또한 다중 채권의 형성에 대한 설명을 제공합니다. 두 개의 피 오비탈의 측면 오버랩은 파이 본드를 발생시합니다.
그러나, 파이 본드는 두 원자 사이에 시그마 채권이 이미 존재하는 경우에만 이중 및 삼중 채권으로 형성 될 수 있습니다. 파이 본드는 비핵화 축의 반대편에 존재하기 때문에 파이 본드는 이 축을 중심으로 회전할 수 없습니다.

원자가 결합 이론 및 혼성 오비탈

Valence Bond Theory and Hybridized Orbitals

원자가 결합 이론에 따르면 공유 결합은 (1) 한 원자의 오비탈이 두 번째 원자의 궤도와 겹치고 (2) 각 오비탈의 단일 전자가 결합하여 전자쌍을 형성할 때 발생합니다. 공유 결합의 강도는 관련된 궤도의 중첩 정도에 따라 달라집니다. 두 핵 사이의 직선에서 오비탈이 겹칠 때 최대 겹침이 가능합니다.

σ 결합(루이스 구조의 단일 결합)은 전자 밀도가 핵간 축을 따르는 영역에 집중되는 공유 결합입니다. π 결합은 두 개의 p 오비탈이 나란히 겹쳐서 발생하는 공유 결합입니다. π 결합에서 궤도 중첩 영역은 핵간 축의 반대편에 있고 축을 따라 노드(전자를 찾을 확률이 없는 평면)가 있습니다. 모든 단일 결합은 σ 결합인 반면, 다중 결합은 σ 결합과 π 결합으로 구성됩니다.

원자가 분자로 결합되면 원자 오비탈의 파동 함수가 결합되어 다양한 모양을 갖는 새로운 수학적 설명을 생성할 수 있습니다. 이 과정을 혼성화라고 하며 수학적으로 원자 궤도의 선형 결합을 통해 수행됩니다. 생성된 새로운 궤도를 하이브리드 오비탈이라고 합니다.

공유 결합된 원자에서만 형성되는 하이브리드 오비탈의 모양과 방향은 고립된 원자의 원자 오비탈과 다릅니다. 하이브리드 오비탈의 수는 이를 생성하기 위해 결합된 원자 오비탈의 수와 같습니다. 하이브리드 궤도 집합의 모든 궤도는 모양과 에너지가 동일하며 방향은 VSEPR 이론에 의해 예측됩니다. 혼성 오비탈은 겹쳐서 σ 결합을 형성하고, 혼성화되지 않은 오비탈은 겹쳐서 π 결합을 형성합니다.

예를 들어, 탄소의 들뜬 상태에서 하나의 2s 오비탈과 세 개의 2p 오비탈이 혼성화되어 사면체 방향의 축퇴 혼성 sp3 오비탈 4개가 생성됩니다. 메탄 분자에서 4개의 수소 원자 각각의 1s 궤도는 탄소 원자의 4개의 sp3 궤도 중 하나와 겹쳐 시그마(σ) 결합을 형성합니다.

마찬가지로, 탄소의 2s 오비탈 하나와 2p 오비탈 두 개를 혼합하면 삼각 평면 기하학을 갖는 등가의 sp2 혼성 오비탈 3개가 생성되는 반면, 2s 오비탈 하나와 2p 오비탈 중 하나의 혼성화는 서로 180° 방향으로 향하는 두 개의 sp 오비탈을 생성합니다.

원자가 하위 껍질에 d 오비탈이 있는 원자의 경우 5개의 원자가 껍질 원자 오비탈(s 1개, p 3개 및 d 궤도 중 1개)의 혼성화는 삼각 쌍뿔 기하학을 갖는 5개의 sp3d 혼성 오비탈을 제공합니다. 6개의 혼성 오비탈의 팔면체 배열은 6개의 원자가 껍질 원자 오비탈(1개의 s, 3개의 p 및 2개의 d 오비탈)을 혼합하여 얻어지며, 이는 6개의 sp3d2 혼성 오비탈을 생성합니다.

이 문서는 에서 발췌되었습니다. <a href="https://openstax.org/books/chemistry-2e/pages/8-1-valence-bond-theory">Openstax, Chemistry 2e, Section 8.1 Valence Bond Theory</a> and <a href="https://openstax.org/books/chemistry-2e/pages/8-2-hybrid-atomic-orbitals">Section 8.2 Hybrid Atomic Orbitals</a>.

원자가 결합 이론에 따르면, 공유 결합은 (1) 한 원자의 궤도가 두 번째 원자의 궤도와 겹치고 (2) 단일 ...

valence-bond-theory-and-hybridized-orbitals

Education

교육

JoVE Core

Organic Chemistry

유기 화학

Unit 1

제1단원

Covalent Bonding and Structure

공유 결합과 구조

KEY TERMS AND CONCEPTS

주요 용어 및 개념

covalent bond overlap and orbital hybridization

Covalent bonds form when orbitals on two atoms overlap and their single electrons pair up. The bond is stronger when the overlap is greater. Maximum overlap happens when the orbitals meet along a direct line between the two nuclei.

A sigma bond, or σ bond, is the kind of covalent bond found in a single bond in a Lewis structure. In a σ bond, electron density is concentrated along the internuclear axis. A pi bond, or π bond, forms when two p orbitals overlap side by side. In a π bond, the overlap lies on opposite sides of the internuclear axis, and a node with no electron probability lies along the axis. Single bonds are σ bonds, while multiple bonds include both σ and π bonds.

When atoms join in a molecule, atomic orbital wave functions can combine to make new orbital shapes. This process is called hybridization, and it is described by the linear combination of atomic orbitals. The new orbitals are called hybrid orbitals. They form only in covalently bonded atoms, and their shapes and orientations differ from those of atomic orbitals in isolated atoms. The number of hybrid orbitals matches the number of atomic orbitals used to make them. Orbitals in one hybrid set have the same shape and energy, and their directions follow VSEPR theory. Hybrid orbitals form σ bonds, while unhybridized orbitals form π bonds.

Carbon shows this pattern clearly. In its excited state, one 2s orbital and three 2p orbitals hybridize to form four equivalent sp3 orbitals arranged tetrahedrally. In methane, each hydrogen 1s orbital overlaps with one carbon sp3 orbital to make a σ bond. One 2s orbital and two 2p orbitals can also mix to make three equivalent sp2 orbitals with trigonal planar geometry. When one 2s orbital mixes with one 2p orbital, two sp orbitals form and point 180° apart.

Atoms with d orbitals in the valence shell can form larger hybrid sets. Mixing five valence shell atomic orbitals, one s, three p, and one d, gives five sp3d hybrid orbitals with trigonal bipyramidal geometry. Mixing six valence shell atomic orbitals, one s, three p, and two d, gives six sp3d2 hybrid orbitals with octahedral geometry.

Covalent Bond Overlap and Orbital Hybridization

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Learn how orbital overlap forms sigma and pi bonds, then see how hybridization creates sp3, sp2, sp, sp3d, and sp3d2 orbitals in molecules.

Covalent Bond Overlap and Orbital Hybridization | JoVE K12

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Covalent Bond Overlap and Orbital Hybridization

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