7.64

SECTION 7

TABLE 7.26 Absorption Frequencies of Miscellaneous Bands (Continued)

Group

Band, cm 1

Remarks

Inorganic ions

Ammonium

3300–

3030

Several bands, all strong

Cyanate

2220–

2130

(s)

Cyanide

2200–

2000

Carbonate

1450–

1410

Hydrogen sulfate

1190–

1160

(s)

1180–

1000

(s)

880–

840 (m)

Nitrate

1410–

1350

(vs)

860–

800 (m)

Nitrite

1275–

1230

(s)

835–

800 (m)

Shoulder

Phosphate

1100–

1000

Sulfate

1130–

1080

(s)

Thiocyanate

ca 2050 (s)

Class

Band, cm 1

Remarks

Acetylenes

9800–9430

6580–6400 (1.0)

Overtone of #CH stretching

Alcohols (nonhydrogen-bonded)

7140–7010 (2.0)

Overtone of OH stretching

Aldehydes

Aliphatic

4640–4520 (0.5)

Combination of C"O and CH

stretchings

Aromatic

ca 8000

ca 4525

ca 4445

Formate

4775–4630 (1.0)

SPECTROSCOPY

7.65

TABLE 7.27

Absorption Frequencies in the Near Infrared (Continued)

Class

Band, cm 1

Remarks

Alkanes

9CH3

9000–

8350

(0.02)

5850–

5660

(0.1)

4510–

4280

(0.3)

9CH2 9

9170–

8475

(0.02)

5830–

6640

(0.1)

4420–

4070

(0.25)

CH

8550–

8130

All bands very weak

7000–

6800

5650–

5560

Cyclopropane

6160–

6060

4500–

4400

Alkenes

C "C

6850–

6370

(1.0)

H

C "CH2 and 9CH "CH2

7580–

7300

(0.02)

6140–

5980

(0.2)

4760–

4700

(1.2)

H

H

C "C

4760–

4660

(0.15)

Trans isomers have no unique bands.

9O9CH"CH2

6250–

6040

(0.3)

9CO9CH"CH2

7580–

7410

(0.02)

6190–

5990

(0.3)

4820–

4750

(0.2–0.5)

Amides

Primary

7400–

6540

(0.7)

Two bands; overtone of NH stretch

5160–

5060

(3.0)

Second overtone of C"O stretch;

5040–

4990

(0.5)

second overtone of NH deforma-

4960–

4880

(0.5)

tion; combination of C"O and NH

Secondary

7330–

7140

(0.5)

Overtone of NH stretch

5050–

4960

(0.4)

Combination of NH stretch and NH

bending

Amines, aliphatic

Primary

9710–

9350

Second overtone of NH stretch

6670–

6450

(0.5)

Two bands; overtone of NH stretch

5075–

4900

(0.7)

Two bands; combination of NH

stretch and NH bending

Secondary

9800–

9350

Second overtone of NH stretch

6580–

6410

(0.5)

Overtone of NH stretch

Amines, aromatic

Primary

9950–

9520

(0.4)

7040–

6850

(0.2)

6760–

6580

(1.4)

5140–

5040

(1.5)

Secondary

10 000–

9710

6800–

6580

(0.5)

7.66

SECTION 7

TABLE 7.27 Absorption Frequencies in the Near Infrared (Continued)

Class

Band, cm 1

Remarks

Aryl-H

7660–7330 (0.1)

6170–5880 (0.1)

Overtone of CH stretch

Carbonyl

5200–5100

Carboxylic acids

7000–6800

Epoxide (terminal)

6135–5960 (0.2)

4665–4520 (1.2)

Cyclopropane bands in same region

Glycols

7140–7040

Hydroperoxides

Aliphatic

6940–6750 (2.0)

4960–4880 (0.8)

Aromatic

7040–6760 (1.0)

Two bands

4950–4850 (1.3)

Imides

9900–9620

6540–6370

Nitriles

5350–5200 (0.1)

Oximes

7140–7050

Phosphines

5350–5260 (0.2)

Phenols

Nonbonded

7140–6800 (3.0)

5000–4950

Intramolecularly bonded

7000–6700

Thiols

5100–4950 (0.05)

SPECTROSCOPY

7.67

TABLE 7.28 Infrared Transmitting Materials

Wavelength

Wavenumber

Refractive

range,

range,

index at

Material

m

cm 1

2 m

NaCl, rock salt

0.25–

17

40

000–

590

1.52

KBr, potassium bromide

0.25–

25

40

000–

400

1.53

KCl, potassium chloride

0.30–

20

33

000–

500

1.5

AgCl, silver chloride*

0.40–

23

25

000–

435

2.0

AgBr, silver bromide*

0.50–

35

20

000–

286

2.2

CaF2, calcium fluoride (Irtran-3)

0.15–

9

66

700–

1 110

1.40

BaF2, barium fluoride

0.20–

11.5

50

000–

870

1.46

MgO, magnesium oxide (Irtran-5)

0.39–

9.4

25

600–

1 060

1.71

CsBr, cesium bromide

1–

37

10

000–

270

1.67

CsI, cesium iodide

1–

50

10

000–

200

1.74

TlBr-TlI, thallium bromide-iodide

0.50–

35

20

000–

286

2.37

(KRS-5)*

ZnS, zinc sulfide (Irtran-2)

0.57–

14.7

17

500–

680

2.26

ZnSe, zinc selenide* (vacuum deposited)

1–

18

10

000–

556

2.45

(Irtran-4)

CdTe, cadmium telluride (Irtran-6)

2–

28

5

000–

360

2.67

Al2O3, sapphire*

0.20–

6.5

50

000–

1538

1.76

SiO2, fused quartz

0.16–

3.7

62

500–

2 700

Ge, germanium*

0.50–

16.7

20

000–

600

4.0

Si, silicon*

0.20–

6.2

50

000–

1 613

3.5

Polyethylene

16–

300

625–

33

1.54