Infrared studies of aragonite, calcite, and vaterite type structures in the borates, carbonates, and nitrates

Abstract

Infrared absorption spectra have been obtained on the alk ali nitrates, the divalent m etal carbonates, a nd t he rare eart h borates which assume t he aragoni te, calcitc, or vaterite cr ystal struct ures. It was observed t hat simi lar str uct ures gi ve rise to analogo us spectra except for t he carbonate and borates having the vaterite str uct ure. The marked differences o~scr~e d in t hese latter spectra. a re disc ussed. Frequency s hifts produ ced by cation s ubs t ltutlOn are ascnbed to repulslOn between closed electro n shells of oxyge n atoms . It is concluded t h at t his repulsive force determines the s tru cture type in the rare earth b~rates .

The presence of vaterite in bonding mortars of marble inlays from Florence Cathedral

“…1. Despite literature claims (Weir and Lippincott, 1961;Sato and Matsuda, 1969;Ducloux et al, 1987;Andersen and Brecevic, 1991) vaterite shows only one absorption at 1476 cm -1 due to the CO 2-asymmetrical stretchin~ (v3), while the other absorptions at 876 and 850 cm-(out of plane bending, v2), and at 746 cm -1 (in plane bending, v4) agree with the data reported in the literature mentioned above. In this case, the Vl vibration around 1100 cm -1 was not detectable because of the presence of hydrated calcium silicoaluminates.…”

Identification of "Chocolate Pearls" Treated by Ballerina Pearl Co.

“…However, the 878 cm −1 band, which was consistently observed in all the untreated Tahitian cultured pearls, matched the peak position of calcite well. In aragonite, the same peak usually occurs at higher wavenumbers than 860 cm −1 (Weir and Lippincott, 1961;Adler and Kerr, 1962;Frech et al, 1980). We believe this peak is not related to calcite (as shown by the lack of calcite in the Raman spectra), so the cause of this relatively strong absorption at 878 cm −1 remains unclear.…”

Infrared spectra of the hydrated borates

“…In addition , the fact that, band for band the frequenci es are the same within experim en tal error may be interpre ted to mean that th e mat erials are che mi call y and structurally identical. Thi s conclusion is based on previous studi es which s how ed that c hange of anion or crystal structure generally produces s hifting of some bands in th e infrared s pectrum [42]. The close similarity in the spectra of all three min erals listed in table 10 indicates that the anions are similar.…”