原子轨道在量子力学里到底是什么？
What exactly is an atomic orbital in quantum mechanics?
它是波函数 ψ 的空间分布，|ψ|² 给出电子在某处出现的概率密度，并非经典的“轨道”轨迹。
It is the spatial distribution of a wavefunction ψ; |ψ|² gives the probability density of finding an electron, not a classical orbit path.
难度 专业 · 适合 高中(15-18)
CC BY 4.0 · 已核验 · Verified 2026-08-23 · 2 条独立证据
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Atkins, de Paula, Keeler,《Atkins' Physical Chemistry》第11版,Oxford University Press,2018
P. Atkins, J. de Paula and J. Keeler, Atkins' Physical Chemistry, 11th ed., Oxford University Press, 2018
独立核验依据 · Independent verification: 核验依据 2 ISBN 978-0-19-884781-6 (11th ed., Oxford University Pres
#薛定谔 #轨道 #概率
如何用分子轨道理论解释氧气（O₂）的顺磁性？
How does molecular orbital theory explain the paramagnetism of oxygen (O₂)?
在分子轨道理论中，O₂ 的 16 个电子按能级顺序填充后，在能量较高的 π* 反键轨道上留下两个自旋平行的未成对电子。根据洪特规则，这两个电子分占两个简并的 π* 轨道且自旋相同，使分子具有净磁矩。价键理论因假设所有电子成对而无法解释这一现象。
In molecular orbital theory, O₂'s 16 electrons fill orbitals in order of energy, leaving two unpaired electrons of parallel spin in the higher-energy degenerate π* antibonding orbitals. Hund's rule places these electrons in separate π* orbitals with the same spin, giving the molecule a net magnetic moment. Valence bond theory fails to predict this because it assumes all electrons are paired.
难度 专业 · 适合 高中(15-18)
CC BY 4.0 · 已核验 · Verified 2026-11-02
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《物理化学》(傅献彩, 第五版) 分子结构章；IUPAC（物理化学术语，2007）
Atkins & de Paula, Physical Chemistry, molecular orbital chapter; IUPAC (Quantities, Units and Symbols in Physical Chemistry, 2007)
独立核验依据 · Independent verification: 核验依据 1 OPENLIBRARY 标识 /works/OL16623359W：Quantities, units, and
#分子轨道 #顺磁性 #反键轨道 #洪特规则
薛定谔方程在化学中有什么意义？它和原子轨道是什么关系？
What is the significance of the Schrödinger equation in chemistry, and how is it related to atomic orbitals?
薛定谔方程是量子力学的核心方程，描述微观粒子波函数随空间与时间的演化。求解氢原子定态薛定谔方程得到一系列本征函数和本征值，分别对应原子轨道及其能量（能级）。这些轨道的量子数 n、l、m 规定了电子的壳层、形状和空间取向。
The Schrödinger equation is the central equation of quantum mechanics, describing how a particle's wavefunction evolves in space and time. Solving its time-independent form for the hydrogen atom yields eigenfunctions and eigenvalues that correspond to atomic orbitals and their energy levels. The quantum numbers n, l, and m define the shell, shape, and spatial orientation of each orbital.
难度 专业 · 适合 高中(15-18)
CC BY 4.0 · 已核验 · Verified 2026-11-03
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《物理化学》(傅献彩, 第五版) 量子力学基础章；IUPAC（物理化学术语，2007）
Atkins & de Paula, Physical Chemistry, quantum foundations chapter; IUPAC (Quantities, Units and Symbols in Physical Chemistry, 2007)
独立核验依据 · Independent verification: 核验依据 1 OPENLIBRARY 标识 /works/OL16623359W：Quantities, units, and
#薛定谔方程 #波函数 #原子轨道 #量子数
摩根圆形指纹是怎样把一个分子的局部结构环境压成一串二进制位的?
How does the Morgan circular fingerprint compress a molecule's local structural environments into a string of binary bits?
算法先给每个原子赋初值不变量(元素、形式电荷、连接度),随后逐轮合并邻近原子的标识,得到半径不断扩张的子结构哈希。各半径层的特征再折叠进固定长度的位向量,供相似度比较与虚拟筛选使用。由于结果与原子编号无关,同一分子总能得到一致的指纹;代价是哈希可能碰撞,提高维度可以稀释冲突。
Each atom first receives an initial invariant (element, formal charge, connectivity); successive rounds then merge neighboring identifiers, producing substructure hashes of ever larger radius. Features from every radius layer are folded into a fixed-length bit vector ready for similarity comparison and virtual screening. Because the result ignores atom numbering, one molecule always yields one consistent fingerprint; hash collisions are the price, diluted by raising dimensionality.
难度 专业 · 适合 高中(15-18)
CC BY 4.0 · 已核验 · Verified 2026-11-04
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Rogers & Hahn,《Extended-Connectivity Fingerprints》,Journal of Chemical Information and Modeling,2010 (DOI: 10.1021/ci100050t)
Rogers & Hahn, 'Extended-Connectivity Fingerprints', Journal of Chemical Information and Modeling, 2010, DOI: 10.1021/ci100050t
独立核验依据 · Independent verification: 核验依据 1 Crossref DOI 10.1021/ci100050t
#分子指纹 #结构相似度
密度泛函理论（DFT）的基本思想是什么？为什么它在计算化学中如此常用？
What is the basic idea of density functional theory (DFT), and why is it so widely used in computational chemistry?
DFT 由 Hohenberg–Kohn 定理奠基，其核心是把多电子体系的基态能量表示为电子密度而非多体波函数的泛函，从而将 3N 维问题降维。Kohn–Sham 方程进一步用无相互作用电子的参考体系逼近真实体系。相比从头算方法，DFT 在精度与计算成本间取得较好平衡，因而广泛用于分子与材料性质预测。
DFT is founded on the Hohenberg–Kohn theorems, which state that the ground-state energy of a many-electron system is a functional of the electron density rather than the many-body wavefunction, reducing a 3N-dimensional problem. The Kohn–Sham equations approximate the real system with a reference of non-interacting electrons. Compared with ab initio methods, DFT balances accuracy and cost, making it popular for predicting molecular and material properties.
难度 专业 · 适合 高中(15-18)
CC BY 4.0 · 已核验 · Verified 2026-11-04
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W. Kohn 与 L. J. Sham, Phys. Rev. 140, A1133 (1965);Kohn 诺贝尔演讲 (1998)
W. Kohn & L. J. Sham, Phys. Rev. 140, A1133 (1965); Kohn Nobel Lecture (1998)
独立核验依据 · Independent verification: 核验依据 1 Crossref DOI 10.1103/physrev.140.a1133
#密度泛函理论 #Hohenberg-Kohn #Kohn-Sham #计算化学
前线轨道理论如何预测周环反应的立体化学选择性？
How does frontier molecular orbital theory predict the stereochemical selectivity of pericyclic reactions?
福井谦一的前线轨道理论用 HOMO 与 LUMO 的对称性与相位重叠判断周环反应是否对称允许。例如电环化反应中，加热与光照分别由基态 HOMO 或激发态轨道的终端相位决定顺旋或对旋模式。该理论把 Woodward–Hoffmann 选择规则转化为直观的轨道相互作用图像。
Fukui's frontier orbital theory predicts whether a pericyclic reaction is symmetry-allowed by examining the symmetry and phase overlap of the HOMO and LUMO. In electrocyclic reactions, for example, thermal and photochemical conditions select conrotatory or disrotatory modes based on the terminal phases of the ground-state HOMO or excited-state orbital. This frames the Woodward–Hoffmann rules as intuitive orbital interactions.
难度 专业 · 适合 高中(15-18)
CC BY 4.0 · 已核验 · Verified 2026-08-23
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Brown, LeMay 等,《Chemistry: The Central Science》第14版,Pearson,2017
T. L. Brown et al., Chemistry: The Central Science, 14th ed., Pearson, 2017
#前线轨道 #周环反应 #Woodward-Hoffmann #电环化
什么是 HOMO 和 LUMO？它们在化学反应中有什么作用？
What are the HOMO and LUMO, and what roles do they play in chemical reactions?
HOMO（最高占据分子轨道）是分子中能量最高、已被电子占据的轨道，LUMO（最低未占分子轨道）是能量最低、尚未被电子占据的轨道。两者合称前线轨道，其能隙大小决定了分子的电子激发难易与化学稳定性。在反应中，电子通常从亲核试剂的 HOMO 流入亲电试剂的 LUMO。
The HOMO (highest occupied molecular orbital) is the molecule's highest-energy orbital that contains electrons, while the LUMO (lowest unoccupied molecular orbital) is the lowest-energy orbital with no electrons. Together called frontier orbitals, their energy gap determines how easily a molecule is electronically excited and how chemically stable it is. In reactions, electron flow typically runs from the nucleophile's HOMO into the electrophile's LUMO.
难度 进阶 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Brown, LeMay 等,《Chemistry: The Central Science》第14版,Pearson,2017
T. L. Brown et al., Chemistry: The Central Science, 14th ed., Pearson, 2017
#分子轨道 #前线轨道 #HOMO #LUMO
氢键是什么？它对水的性质有什么影响？
What is a hydrogen bond, and how does it affect the properties of water?
氢键是带正电的氢原子与电负性强的原子（如 O、N、F）之间形成的弱静电相互作用，键能约 10–40 kJ/mol。在水中，氢键使分子缔合，显著提高沸点、比热和表面张力，并导致冰的密度小于液态水。这些特性是生命体系得以存在的重要物理基础。
A hydrogen bond is a weak electrostatic interaction between a positively polarized hydrogen atom and a highly electronegative atom such as O, N, or F, with an energy of roughly 10–40 kJ/mol. In water, hydrogen bonds promote molecular association, raising the boiling point, specific heat, and surface tension, and make ice less dense than liquid water. These features underpin many life-supporting properties of water.
难度 进阶 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-11-03
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《物理化学》(傅献彩, 第五版)；IUPAC（物理化学术语，2007）
IUPAC (Quantities, Units and Symbols in Physical Chemistry, 2007); Atkins & de Paula, Physical Chemistry
独立核验依据 · Independent verification: 核验依据 1 OPENLIBRARY 标识 /works/OL16623359W：Quantities, units, and
#氢键 #水 #分子间作用 #沸点
什么是共振结构（离域）？它和真实分子的关系是什么？
What are resonance structures (delocalization), and how do they relate to the real molecule?
共振结构是用多个经典路易斯结构共同描述一个无法用单一结构准确表达的分子，例如碳酸根与苯。真实分子是这些极限式的共振杂化体，电子在多个原子间离域，使体系能量低于任一单一结构。共振不是结构间的快速互变，而是一种离域的稳定化效应。
Resonance structures are several classical Lewis forms used together to describe a molecule that cannot be captured by a single structure, such as the carbonate ion or benzene. The real molecule is a resonance hybrid of these contributors, with electrons delocalized over several atoms, lowering the energy below any single form. Resonance is not rapid interconversion but a stabilization from delocalization.
难度 进阶 · 适合 大众
CC BY 4.0 · 来源待核验 · Source pending review
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出处备注：著录含书名，但缺版次 / 出版社 / 年份中的一部分，需编辑补全后才能做独立比对。
《有机化学》(邢其毅, 第四版) 芳香族化合物章；IUPAC《化学术语总表》(Gold Book, 2014 修订)
IUPAC Gold Book (Compendium of Chemical Terminology, 2014); Clayden, Greeves & Warren, Organic Chemistry, aromaticity chapter
#共振结构 #离域 #共振杂化 #路易斯结构
SMILES 与 InChI 这两种分子线性表示法的核心设计目标有什么不同?
How do SMILES and InChI differ in their core design goals as linear molecular representations?
SMILES 由 Daylight 提出,目标是用紧凑直观的字符串表达连接关系,同一分子允许多种合法写法,便于人读和人写,规范化和同构判定需要额外算法支持。InChI 由 IUPAC 主导,目标是生成唯一的标准化标识符:按固定规则规范化电荷、互变异构和立体信息,使得结构相同的分子必然得到相同字符串,适合数据库索引与去重。简言之 SMILES 偏向表达自由,InChI 偏向身份唯一。
SMILES, introduced by Daylight, aims at compact human-readable strings encoding connectivity; one molecule may have many valid writings, and canonicalization requires extra algorithms. InChI, led by IUPAC, targets a unique standardized identifier: fixed normalization rules for charges, tautomers, and stereochemistry guarantee that identical structures always produce identical strings, suiting database indexing and deduplication. In short, SMILES favors expressive freedom while InChI favors identity uniqueness.
难度 进阶 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-11-05
来源 · Source
Heller, McNaught, Pletnev, Stein,《InChI, the IUPAC International Chemical Identifier》,Journal of Cheminformatics,2015 (DOI: 10.1186/s13321-015-0068-4)
Heller, McNaught, Pletnev, Stein, 'InChI, the IUPAC International Chemical Identifier', Journal of Cheminformatics, 2015, DOI: 10.1186/s13321-015-0068-4
独立核验依据 · Independent verification: 核验依据 1 Crossref DOI 10.1186/s13321-015-0068-4
#分子表示 #化学信息学标准
碳原子常见的杂化方式有哪些？各对应什么空间构型？
What are the common hybridization states of carbon, and what geometries do they give?
碳常见 sp³、sp² 和 sp 三种杂化。sp³ 杂化形成四个等价轨道，呈四面体构型（如甲烷）；sp² 杂化形成三个平面轨道，呈平面三角形（如乙烯）；sp 杂化形成两个直线型轨道（如乙炔）。杂化方式决定了键角与分子骨架形状。
Carbon commonly adopts sp³, sp², and sp hybridization. sp³ gives four equivalent orbitals in a tetrahedral arrangement (as in methane), sp² gives three coplanar orbitals in a trigonal arrangement (as in ethene), and sp gives two linear orbitals (as in ethyne). The hybridization dictates bond angles and the molecular skeleton.
难度 进阶 · 适合 初中(12-15)
CC BY 4.0 · 已核验 · Verified 2026-11-03
来源 · Source
《有机化学》(邢其毅, 第四版) 第一章；IUPAC《化学术语总表》(Gold Book, 2014 修订)
IUPAC Gold Book (Compendium of Chemical Terminology, 2014); Carey & Sundberg, Advanced Organic Chemistry, Vol. 1
独立核验依据 · Independent verification: 核验依据 1 CROSSREF 标识 10.1007/b114293：Advanced Organic Chemistry（2
#杂化轨道 #四面体 #平面三角形 #碳