双语化学辞典Chem Lexicon

红外特征吸收表IR absorption table — characteristic group frequencies

红外吸收来自改变偶极矩的分子振动。按胡克定律，键越强、原子越轻，伸缩振动波数越高：\(\tilde\nu = \frac{1}{2\pi c}\sqrt{k/\mu}\)。下表给出常见官能团的特征吸收范围；实际位置受共轭、氢键、环张力、取代基电子效应和物态影响，应结合多个谱带综合判断。

IR absorption comes from vibrations that change the dipole moment. By Hooke’s law, stronger bonds and lighter atoms vibrate at higher wavenumber: \(\tilde\nu = \frac{1}{2\pi c}\sqrt{k/\mu}\). The table lists characteristic ranges; real positions shift with conjugation, hydrogen bonding, ring strain, substituent effects and phase, so assign bands in combination.

谱区速览Spectral regions

4000–2500X–H 伸缩区：O–H、N–H、C–H、S–HX–H stretching: O–H, N–H, C–H, S–H
2500–2000三键与累积双键区：C≡N、C≡C、C=C=O、N=C=O、CO₂Triple bonds & cumulenes: C≡N, C≡C, ketenes, isocyanates, CO₂
2000–1500双键区：C=O、C=N、C=C、N=O，芳环骨架，N–H 弯曲Double bonds: C=O, C=N, C=C, N=O, aromatic ring modes, N–H bending
1500–400指纹区：C–O、C–N、C–X 伸缩，各类弯曲振动，分子整体特征Fingerprint region: C–O, C–N, C–X stretches, bending modes — characteristic of the whole molecule

吸收位置图Band positions

点击任意谱带跳到下表对应行。2000 cm⁻¹ 以上标尺压缩一半，与常见红外谱图一致。Click a band to jump to its table row. Above 2000 cm⁻¹ the scale is compressed, as on most IR spectra.

X–H 伸缩区X–H stretch三键区triple bonds双键区double bonds指纹区 1500–400 cm⁻¹fingerprint region40003600320028002400200018001600140012001000800600400⇤ 标尺变化 scale change波数 Wavenumber / cm⁻¹伯、仲胺，酰胺 · 1° & 2° amines, amides：3500–3300 cm⁻¹NH伸缩 stretchM伯、仲胺，酰胺1° & 2° amines, amides醇、酚 · Alcohols, phenols：3550–3200 cm⁻¹OH伸缩 stretchSB醇、酚Alcohols, phenols端炔 · Terminal alkynes：3330–3260 cm⁻¹CH伸缩 stretchSN端炔Terminal alkynes烯烃、芳烃 · Alkenes, aromatics：3100–3000 cm⁻¹CH伸缩 stretchM烯烃、芳烃Alkenes, aromatics羧酸 · Carboxylic acids：3300–2500 cm⁻¹OH伸缩 stretchSB羧酸Carboxylic acids烷烃 · Alkanes：2970–2850 cm⁻¹CH伸缩 stretchS烷烃Alkanes醛（双峰） · Aldehydes (2 bands)：2850–2700 cm⁻¹CH伸缩 stretchW醛（双峰）Aldehydes (2 bands)硫醇 · Thiols：2600–2550 cm⁻¹SH伸缩 stretchW硫醇Thiols腈 · Nitriles：2260–2210 cm⁻¹CN伸缩 stretchMN腈Nitriles炔 · Alkynes：2260–2100 cm⁻¹CC伸缩 stretchW炔AlkynesCO伸缩 stretchS酰氯 · Acyl chlorides：1815–1785 cm⁻¹酰氯 Acyl chlorides1815–1785酸酐（双峰） · Anhydrides (2 bands)：1830–1740 cm⁻¹酸酐（双峰） Anhydrides (2 bands)1830–1740酯 · Esters：1750–1735 cm⁻¹酯 Esters1750–1735醛 · Aldehydes：1740–1720 cm⁻¹醛 Aldehydes1740–1720酮 · Ketones：1725–1705 cm⁻¹酮 Ketones1725–1705羧酸 · Carboxylic acids：1725–1700 cm⁻¹羧酸 Carboxylic acids1725–1700酰胺 · Amides：1690–1630 cm⁻¹酰胺 Amides1690–1630烯烃 · Alkenes：1680–1620 cm⁻¹CC伸缩 stretchV烯烃Alkenes伯胺 · 1° amines：1650–1580 cm⁻¹NH弯曲 bendM伯胺1° amines芳环（多峰） · Aromatics (several)：1600–1450 cm⁻¹CC环骨架 ring stretchM芳环（多峰）Aromatics (several)硝基 · Nitro：1560–1500 cm⁻¹NO反对称伸缩 asym. stretchS硝基Nitro烷烃 · Alkanes：1470–1350 cm⁻¹CH弯曲 bendM烷烃Alkanes硝基 · Nitro：1370–1300 cm⁻¹NO对称伸缩 sym. stretchS硝基Nitro醇、醚、酯、羧酸 · Alcohols, ethers, esters, acids：1300–1000 cm⁻¹CO伸缩 stretchS醇、醚、酯、羧酸Alcohols, ethers, esters, acids胺 · Amines：1340–1020 cm⁻¹CN伸缩 stretchM胺Amines烯烃 · Alkenes：995–665 cm⁻¹CH面外弯曲 out-of-plane bendS烯烃Alkenes芳环（取代方式） · Aromatics (substitution)：860–680 cm⁻¹CH面外弯曲 out-of-plane bendS芳环（取代方式）Aromatics (substitution)C–Cl 550–850，C–Br 515–690 · Alkyl chloride / bromide：850–515 cm⁻¹CX伸缩 stretchSC–Cl 550–850，C–Br 515–690Alkyl chloride / bromide

图例 KeyS强 strongM中 mediumW弱 weakV可变 variableB宽 broadN尖 narrow

查表Look-up table

官能团 Group键 / 振动 Bond / mode波数 cm⁻¹强度 Intensity说明 Notes
游离醇羟基Alcohol O–H, freeO–H 伸缩 str3650–3584m, sh稀溶液或气相中可见seen in dilute solution or gas phase
缔合醇、酚羟基Alcohol / phenol O–H, H-bondedO–H 伸缩 str3550–3200s, br宽而强，最常见的“醇峰”broad and strong — the usual alcohol band
羧酸羟基Carboxylic acid O–HO–H 伸缩 str3300–2500s, very br极宽，常与 C–H 峰重叠，二聚体氢键所致very broad, overlaps C–H; from the H-bonded dimer
水（结晶水、吸附水）WaterO–H 伸缩 / H–O–H 弯曲3500–3200s, br另在约 1640 有弯曲振动；KBr 压片易吸水plus bending near 1640; KBr pellets pick up water
伯胺 N–HPrimary amine N–HN–H 伸缩 str3500–3300m两个峰（对称与反对称伸缩）two bands (symmetric and antisymmetric)
仲胺 N–HSecondary amine N–HN–H 伸缩 str3350–3310w–m单峰；叔胺无此峰one band; tertiary amines show none
酰胺 N–HAmide N–HN–H 伸缩 str3500–3100m伯酰胺双峰、仲酰胺单峰primary amides two bands, secondary one
铵盐 N⁺–HAmmonium N⁺–HN–H 伸缩 str3200–2250s, br宽而复杂，胺的盐酸盐broad, structured; amine hydrochlorides
炔氢Alkyne ≡C–HC–H 伸缩 str3330–3260s, sh尖锐强峰，端炔的标志sharp and strong — diagnostic of terminal alkynes
芳环 C–HAromatic C–HC–H 伸缩 str3100–3000w–m略高于 3000just above 3000
烯烃 =C–HAlkene =C–HC–H 伸缩 str3100–3010m高于 3000 是不饱和 C–H 的判据above 3000 signals unsaturated C–H
烷基 C–HAlkyl C–HC–H 伸缩 str2970–2850s低于 3000；CH₃ 约 2960/2870，CH₂ 约 2925/2850below 3000; CH₃ ≈ 2960/2870, CH₂ ≈ 2925/2850
醛 C–HAldehyde C(O)–HC–H 伸缩 str2850–2700w–m约 2820 与 2720 两个峰（费米共振），2720 很有诊断价值pair near 2820 and 2720 (Fermi resonance); 2720 is diagnostic
巯基Thiol S–HS–H 伸缩 str2600–2550w弱但位置独特weak but in a clear window
P–HPhosphine P–HP–H 伸缩 str2440–2280m, sh
Si–HSilane Si–HSi–H 伸缩 str2250–2100s
B–HBorane B–HB–H 伸缩 str2600–2350s桥键 B–H–B 约 1500–2100bridging B–H–B ≈ 1500–2100
腈Nitrile C≡NC≡N 伸缩 str2260–2210m, sh共轭使其移向低波数conjugation lowers it
异腈Isonitrile N≡CN≡C 伸缩 str2165–2110s
端炔 C≡CTerminal alkyne C≡CC≡C 伸缩 str2140–2100w–m
内炔 C≡CInternal alkyne C≡CC≡C 伸缩 str2260–2190w / 无对称内炔偶极不变，红外不活性（拉曼活性）symmetric internal alkynes are IR-inactive (Raman-active)
异氰酸酯Isocyanate N=C=O反对称伸缩 asym str2275–2250s, br
异硫氰酸酯Isothiocyanate N=C=S反对称伸缩 asym str2140–2040s, br
叠氮Azide N=N=N反对称伸缩 asym str2160–2090s
重氮Diazo / diazoniumN≡N / C=N=N2300–2100s重氮盐约 2260，重氮烷约 2100diazonium ≈ 2260, diazoalkanes ≈ 2100
烯酮Ketene C=C=O反对称伸缩 asym str2150–2100s
碳二亚胺Carbodiimide N=C=N反对称伸缩 asym str2150–2110s
丙二烯Allene C=C=C反对称伸缩 asym str1980–1900m
二氧化碳（背景）CO₂ (background)反对称伸缩 asym str2365–2335s, 双峰空气中的 CO₂，背景扣除不净时出现atmospheric CO₂ when the background is not subtracted
金属羰基Metal carbonyl M–C≡OC≡O 伸缩 str2125–1850s反馈 π 键越强波数越低；桥羰基 1700–1860stronger π back-donation → lower; bridging CO 1700–1860
酰氯Acyl chlorideC=O 伸缩 str1815–1785s
酸酐AnhydrideC=O 伸缩 str1830–1800 & 1775–1740s两个峰（约 1820 和 1760，相差约 60）two bands (≈1820 and ≈1760, ~60 apart)
γ-内酯γ-LactoneC=O 伸缩 str1795–1760s五元环张力使波数升高five-ring strain raises it
酯Ester (saturated)C=O 伸缩 str1750–1735s配合 1300–1000 两个强 C–O 峰with two strong C–O bands at 1300–1000
α,β-不饱和酯α,β-Unsaturated / aryl esterC=O 伸缩 str1730–1715s
醛Aldehyde (saturated)C=O 伸缩 str1740–1720s共轭醛 1680–1705conjugated 1680–1705
酮Ketone (saturated, acyclic)C=O 伸缩 str1725–1705s环己酮约 1715，环戊酮约 1745，环丁酮约 1780cyclohexanone ≈1715, cyclopentanone ≈1745, cyclobutanone ≈1780
共轭酮、芳酮Conjugated / aryl ketoneC=O 伸缩 str1700–1665s共轭降低约 20–40conjugation lowers by ~20–40
羧酸Carboxylic acidC=O 伸缩 str1725–1700s二聚体；配合 2500–3300 宽 O–Hdimer; with the broad 2500–3300 O–H
羧酸根Carboxylate反对称 / 对称伸缩asym. / sym. str1610–1550s另有约 1400 对称伸缩plus symmetric stretch near 1400
酰胺 I 带Amide IC=O 伸缩 str1690–1630s蛋白质二级结构分析的关键谱带the key band for protein secondary structure
酰胺 II 带Amide IIN–H 弯曲 + C–N 伸缩1570–1510s仲酰胺特有secondary amides
β-内酰胺β-LactamC=O 伸缩 str1760–1730s四元环张力，青霉素类的特征four-ring strain; penicillins
碳酸酯Carbonate (organic)C=O 伸缩 str1780–1740s
氨基甲酸酯Carbamate (urethane)C=O 伸缩 str1740–1690s
脲UreaC=O 伸缩 str1680–1630s
醌QuinoneC=O 伸缩 str1690–1650s
烯烃 C=CAlkene C=CC=C 伸缩 str1680–1620v对称取代时很弱；共轭使其增强并降低weak if symmetric; conjugation strengthens and lowers it
芳环骨架Aromatic ring C=C环伸缩 ring str1600–1450m, 多峰约 1600、1580、1500、1450 一组峰set near 1600, 1580, 1500, 1450
亚胺 / 肟Imine / oxime C=NC=N 伸缩 str1690–1640v
偶氮Azo N=NN=N 伸缩 str1450–1400w反式偶氮红外弱weak for trans-azo compounds
硝基Nitro NO₂反对称 / 对称伸缩asym. / sym. str1560–1500 & 1370–1300s两个强峰：1500–1560 与 1300–1370two strong bands: 1500–1560 and 1300–1370
亚硝基Nitroso N=ON=O 伸缩 str1600–1500s
硝酸酯Nitrate ester O–NO₂反对称伸缩asym. str1660–1620s另有 1270–1285plus 1270–1285
伯胺 N–H 弯曲Primary amine N–H bendN–H 剪式弯曲 scissor1650–1580m
CH₂ 剪式 / CH₃ 反对称弯曲CH₂ scissor / CH₃ asym. bendC–H 弯曲 bend1470–1440m
CH₃ 对称弯曲（伞式）CH₃ umbrella bendC–H 弯曲 bend1385–1370m异丙基、叔丁基处裂分为双峰split into a doublet for isopropyl / tert-butyl
醇、醚、酯的 C–OC–O (alcohols, ethers, esters)C–O 伸缩 str1300–1000s伯醇约 1050，仲醇约 1100，叔醇约 1150；芳醚约 12501° alcohol ≈1050, 2° ≈1100, 3° ≈1150; aryl ether ≈1250
C–NC–N (amines)C–N 伸缩 str1340–1020m芳胺 1250–1340，脂肪胺 1020–1250aryl amines 1250–1340, aliphatic 1020–1250
O–H 面内弯曲O–H in-plane bendO–H 弯曲 bend1420–1330m
磺酰基 SO₂Sulfonyl SO₂反对称 / 对称伸缩asym. / sym. str1370–1300 & 1180–1120s1300–1370 与 1120–1180 两个强峰two strong bands: 1300–1370 and 1120–1180
亚砜 S=OSulfoxide S=OS=O 伸缩 str1070–1030sDMSO 约 1050DMSO ≈ 1050
P=OPhosphoryl P=OP=O 伸缩 str1300–1140s
P–O–CP–O–CP–O 伸缩 str1050–970s
Si–OSi–O (siloxane, silica)Si–O 伸缩 str1130–1000s, br玻璃、硅胶的强宽峰the strong broad band of glass and silica
C–FC–FC–F 伸缩 str1400–1000sCF₃ 常在 1100–1350 多个强峰CF₃ gives several strong bands at 1100–1350
C–ClC–ClC–Cl 伸缩 str850–550s
C–BrC–BrC–Br 伸缩 str690–515s
C–IC–IC–I 伸缩 str600–485s
反式烯烃 =C–H 面外弯曲trans-Alkene =C–H oop bendC–H 面外弯曲 oop980–960s约 965，反式双键的标志≈965, diagnostic of trans C=C
顺式烯烃 =C–H 面外弯曲cis-Alkene =C–H oop bendC–H 面外弯曲 oop730–665m
端烯 =CH₂ 面外弯曲Vinyl / vinylidene oop bendC–H 面外弯曲 oop995–885s乙烯基约 990 和 910；亚乙烯基约 890vinyl ≈990 & 910; vinylidene ≈890
单取代苯面外弯曲Monosubstituted benzene oopC–H 面外弯曲 oop770–730 & 710–690s约 750 与 700 两个强峰two strong bands near 750 and 700
邻二取代苯ortho-Disubstituted benzene oopC–H 面外弯曲 oop770–735s
间二取代苯meta-Disubstituted benzene oopC–H 面外弯曲 oop810–680s约 780 与 690，另有约 880near 780 and 690, plus ≈880
对二取代苯para-Disubstituted benzene oopC–H 面外弯曲 oop860–800s单个强峰a single strong band
芳环泛频区Aromatic overtones / combinations泛频 / 合频overtones / combinations2000–1660w形状指示苯环取代方式pattern indicates the substitution pattern
长链 CH₂ 面内摇摆(CH₂)ₙ rock, n ≥ 4CH₂ 摇摆 rock725–720w–m
无机：碳酸根Carbonate ion CO₃²⁻反对称伸缩asym. str1450–1410s, br另有约 875plus ≈875
无机：硫酸根Sulfate ion SO₄²⁻反对称伸缩asym. str1130–1080s, br另有约 615plus ≈615
无机：硝酸根Nitrate ion NO₃⁻反对称伸缩asym. str1410–1340s另有约 830plus ≈830
无机：磷酸根Phosphate ion PO₄³⁻反对称伸缩asym. str1100–1000s, br
金属–氧Metal–oxygen M–OM–O 伸缩 str700–400m–s氧化物、配合物的低频区oxides and complexes, low-frequency region

强度 Intensity: s 强 strong · m 中 medium · w 弱 weak · v 可变 variable · br 宽 broad · sh 尖 sharp