Spectroscopic, thermal and structural studies on manganous malate crystals

Low molecular weight organic acid salts, markers of old fungi activity in wall paintings

“…The fact that the infrared spectra and XRD patterns obtained do not coincide exactly with the reference data available in the literature [17][18][19] or with the LMWOA salts sintered by us (Fig. 7), may be explained by the extreme complexity of the layers found in the paintings: mixed LMWOA salts showing different degrees of hydration and which are also present in various proportions.…”

“…Both infrared spectra and X-ray diffraction patterns obtained from different samples corresponding to different substrata and painting colours show how these substances are present in various proportions in all the dark spots. The fact that the infrared spectra and XRD patterns obtained do not coincide exactly with the reference data available in the literature [17][18][19] or with the LMWOA salts sintered by us (Fig. 7) may be explained by the extreme complexity of the layers found in the paintings: mixed LMWOA salts showing different degrees of hydration and which are also present in various proportions as shown in Fig.…”

“…20 C]O asymmetric stretching vibration bands of the carboxylate group (carboxylic acid salt) are found in the interval between 1550 and 1600 cm À1 . The bands observed at 1427 or 1440 cm À1 can be attributed to the C-O symmetric stretching vibration of the carboxylate group, 11 but also to the dCH 2 mode of the methylene group 18,25 (a small contribution due to the presence of carbonate, calcium carbonate, cannot be fully withdrawn). The bands observed at 1391 and 1409 cm À1 can be related to the CH 3 asymmetric bending vibration (present in the lactate salt), but also to the C-O symmetric stretching vibration of the carboxylate group.…”

“…The bands observed at 1391 and 1409 cm À1 can be related to the CH 3 asymmetric bending vibration (present in the lactate salt), but also to the C-O symmetric stretching vibration of the carboxylate group. 18,25 The band observed between 1340 and 1350 cm À1 can be associated to the wagging of the CH 2 methylene group or to the CH 3 symmetric bending vibration (present in the lactate salt). The sharp bands at 1051 and 1103 cm À1 might be related to the C-O-stretching of the primary and secondary alcohols, respectively.…”

Growth and characterization of a novel crystal-barium malate trihydrate

“…Optical quality single crystals of appreciable size can be grown by the controlled diffusion of the appropriate ionic species in a neutral gel matrix. Using this method, we have succeeded in growing good crystals of a few malates [9][10][11], malonates [12][13] and maleates [14][15][16]. In this paper, we report for the first time, the growth of crystals of appreciable size by the coordination of malic acid with barium.…”