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Table 3 Inorganic compounds detected by XRD in the samples

From: Comparative chemical investigations of alum treated archaeological wood from various museum collections

Collection

Sample

Major compounds

Minor compounds

Dejbjerg

D-A1624

K-alum

Alunite, gypsum

D-B1624

K-alum

Syngenite

D-C1628

K-alum

Syngenite

D-D1626-A

K-alum

Syngenite

D-D1626-B

K-alum

 

D-E1622-A

K-alum

Gypsum

D-E1622-B

K-alum

 

D-F1629

K-alum

 

Oseberg

N-187D

K-alum, Mercallite

 

N-187L

K-alum

Mercallite

N-207-A

NH4-alum

 

N-207-B

NH4-alum

 

N-250F

K-alum

 

N-250K

K-alum, alunite

 

Glimmingehus

S-5T

K-alum

 

S-125ha

 

Alunite

S-125k

K-alum

Alunite

S-346a

  

S-346d

K-alum, alunite

Syngenite

S-346e

K-alum

Alunite, syngenite

S-383

K-alum

Mercallite

S-383c

K-alum

Mercallite

  1. ‘Major’ and ‘Minor’ refer to the intensity of crystalline peaks in the XRD patterns, which only reflects their relative abundance, and does not reflect the abundance of these compounds relative to the wood material or other amorphous components. ‘Major’ patterns showed intense, clearly defined peaks, such as those seen in Figs. 1 and 2. ‘Minor’ patterns generally appeared as small peaks that were difficult to distinguish from the baseline, relative to the more intense ‘major’ pattern, but could be unambiguously identified as the assigned compound using the software and were consistent with elemental compositions observed by SEM–EDS. Chemical formulae for minerals: K-alum = KAl(SO4)2·12H2O; NH4-alum = NH4Al(SO4)2·12H2O; alunite = KAl3(SO4)2(OH)6; gypsum = CaSO4·2H2O; syngenite = K2Ca(SO4)2·H2O; mercallite = KHSO4
  2. aSamples re-treated with PEG 2000 between 2005 and 2009