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. 2026 Mar 25;16:9969. doi: 10.1038/s41598-026-45511-3

Table 1.

Maxima of sorption bands in FTIR spectra of minerals associated with their WN range (1 between layers, 2 in layers). The absorption peaks correspond to those highlighted in Figures 1, 2 and 3.

valence vibration deformation vibration
region I region II arrow marked region III
ν- OH ν- Si-O ν- Si-O-Si δ- Al-O-Si δ - Si-O-Si
Reference 12 12 12 18 12
WN 3800-2700 1300-850 850-750 650-500 550-400
Sipernat310

I13439

hydrogen bridges

II 1

1096 ν-Si-O

II 2

967 ν-Si-O

 1 801 ν-Si-O-Si III 471 δ-Si-O-Si
Sipernat50

I1 3438

hydrogen bridges

II 1

1097 ν-Si-O

II 2

969 ν-Si-O

 1 798 ν-Si-O-Si III 470 δ-Si-O-Si
Aerosil

I1 3438

hydrogen bridges

II 1

1104 ν-Si-O

II 2

987 ν-Si-O

 1 809 ν-Si-O-Si III 470 δ-Si-O-Si
Rice husk

I1 3448

hydrogen bridges

II 1

1104 ν-Si-O

 1 803 ν-Si-O-Si III 469 δ-Si-O-Si
Natural amorphous silica

I1 3438

hydrogen bridges

II 1

1092 ν-Si-O

II 2

945 ν-Si-O

 1 799 ν-Si-O-Si III 466 δ-Si-O-Si
Kaolin(A)

Ia 3694 Si-OH1

I b3618 Si-OH2

Ic 3439

ν- Al- OH

hydrogen bridges

II a

1114 ν-Si-O

II b

1032 ν-Si-O

II c

1009 ν-Si-O

II d

913 ν-Si-O

 a 796 ν-Si-O-Si IIIa539 δ-Al-O-Si IIIb470 δ-Si-O-Si
Kaolin(B)

I a3696 Si-OH1

I b3619 Si-OH2

Ic 3448

ν- Al-OH

hydrogen bridges

II a

1113 ν-Si-O

II b

1031 ν-Si-O

II c

1007 ν-Si-O

II d

912 ν-Si-O

 a 789 ν-Si-O-Si IIIa537 δ-Al-O-Si IIIb469 δ-Si-O-Si
Kaolin(C)

Ia 3694 Si-OH1

I b3619 Si-OH2

c 3448

ν- Al- OH

hydrogen bridges

II a 

1115 ν-Si-O

II b

1032 ν-Si-O

II c

1010 ν-Si-O

II d

913 ν-Si-O

 a 797 ν-Si-O-Si IIIa539 δ-Al-O-Si IIIb470 δ-Si-O-Si

Montmorillonite

(A)

I1 3630 Si-OH

I2 3421

ν- Al- OH

hydrogen bridges

II 1

1090 ν-Si-O

II 2

1048 ν-Si-O

 1 796 ν-Si-O-Si III1 522 δ-Al-O-Si III2471 δ-Si-O-Si

Montmorillonite

(B)

I1 3621 Si-OH

I2 3438

ν- Al- OH

hydrogen bridges

II

1048 ν-Si-O

 1 798 ν-Si-O-Si III1525 δ-Al-O-Si III2468 δ-Si-O-Si
Illite

I 3438

hydrogen bridges

II

1025 ν-Si-O

 III1 524 δ-Al-O-Si III2 471 δ-Si-O-Si
Vermiculite

I 3414

hydrogen bridges

II

1000 ν-Si-O

 III 450 δ-Si-O-Si
Biotite

I 3438

hydrogen bridges

II

1004 ν-Si-O

 III 461 δ-Si-O-Si
Olivine

I1 3438

hydrogen bridges

II 1

983 ν-Si-O

II 2

885 ν-Si-O

II 3

839 ν-Si-O

III1 605 δ-Si-O-Si*

III2 504 δ-Si-O-Si*

III3 415 δ-Si-O-Si*

*can contain ν-Mg-O vibrations19