## 3 Results and Discussions
### FTIR Spectra Analysis
The shift of the peak between the two samples is due to the influence of the other two crystalline components in sample P1 (SiO\({}_{2}\)--moganite and CaSO\({}_{4}\)--anhydrite) to the specific vibration of crystalline CaCO3, compared with sample P2 where only crystalline CaCO\({}_{3}\) (calcite) was detected by XRD. Absorbed water on the surface of the material is evidenced in both P1 and P2 by the bands at 3805 cm\({}^{-1}\) (P1), 3545 cm\({}^{-1}\) (P1, P2), denoting free O-H groups and 3425 cm\({}^{-1}\) (P1, P2) assigned to O-H groups that can be free or hydrogen bounded [20,21]. Noisy spectra denote H\({}_{2}\)O absorbed into the analyzed samples or hydrated compounds. The water absorbed into the meteoritic material or adsorbed onto the surface of the fragment or of the pores is in accordance with [PERSON] et al. [15], who consider the meteorite as a \"coherent carbonaceous matrix with pores filled with water ice and volatile organics\". [PERSON] et al. [7] reported bands at \(\sim\)3400 cm\({}^{-1}\) for the Murchison and Bells FTIR spectra assigned to H\({}_{2}\)O absorbed of the hydrous silicates. The band at 3805 cm\({}^{-1}\) may also indicate _silanol groups_ (Si-OH) [21]. Vibrations at 3750 cm\({}^{-1}\) (P1, P2), known as specific to silanol bonding to a polymer chain [22], confirmed the Si-OH groups. _Chemical structures with silicon_ are also denoted by the vibrational band at 950 cm\({}^{-1}\), which is assigned to Si-O stretching [7,20,21] and the bands at 853 cm\({}^{-1}\) and 804 cm\({}^{-1}\) are assigned to Si-(CH\({}_{3}\))\({}_{2}\) skeletal vibration and Si-O-C stretching, both in the same range of \(\sim\)850; \(\sim\)800 [21]. Vibrational bands at 3382 cm\({}^{-1}\) (P1, P2), 3306 cm\({}^{-1}\) (P1) and 3317 cm\({}^{-1}\) (P2) and 3252 cm\({}^{-1}\) (P1, P2), indicate the OH groups specific to _carboxylic acids_ in the COOH functional group, but also the possible amino groups (N-H) [21] denoting possible _amino acids_. The large band in the range of 1905 cm\({}^{-1}\)-1699 cm\({}^{-1}\) (P1, P2) is assigned to carbonyl groups, but also to the stretching vibrations of the bonds C-O in the group COOH of _carboxylic acids_[21]. The bond C-O was also confirmed by the band at 1093 cm\({}^{-1}\) (P2), as well as the 864 cm\({}^{-1}\) band (P2) [21]. In the same range of 1905 cm\({}^{-1}\)-1699 cm\({}^{-1}\), the _arenes_ overtones due to _mono-substitution_ (coupled with the 689 cm\({}^{-1}\) band) and _meta di-substitution_ (coupled with the 864 cm\({}^{-1}\) band) were also identified. _Aromatic compounds_ are denoted in the P2 FTIR spectrum by the 3056 cm\({}^{-1}\) band (P2) specific to (ar)C-C groups [21] and the 1536 cm\({}^{-1}\) band specific to the skeletal vibrations of the aromatic bonds, C=C, reported in literature as being in the range of 1610 cm\({}^{-1}\)-1550 cm\({}^{-1}\) (P1) [21]. In the spectrum of the Bells meteorite, the vibrations specific to aromatic C=C were found at about 1600 cm\({}^{-1}\)[7]. The sample P1 spectrum also indicated amides II, NHC=O free and H-bonded (in the same range with C=C aromatic) [21]. The chelated structures are indicated by the bands at 3121 cm\({}^{-1}\) (P1, P2) and are assigned to _calcium carbonate_, CaCO\({}_{3}\), and the vibrations specific to CO\({}_{3}\)\({}^{2-}\) at 1429 cm\({}^{-1}\) (P1) and 1438 cm\({}^{-1}\) (P2) [31] are also present in the FTIR spectra of the two samples. [PERSON] et al. [7] reported bands assigned to carbonates at 1435 cm\({}^{-1}\) and 1450 cm\({}^{-1}\) in the Murchison and Bells meteorite spectrum, respectively. The symmetric stretch modes of the carbonate ions CO\({}_{3}\)\({}^{2-}\) at 1093 cm\({}^{-1}\) (P2) and 874 cm\({}^{-1}\) (P1, P2) out-of-plane bending modes [22; 27; 28; 30] complete the information provided by the FTIR spectrum of the P2 sample, regarding the content in carbonates. The strong peaks at 1429 cm\({}^{-1}\) (P1) and 1438 cm\({}^{-1}\) (P2) also denote the _crystalline state_ due to calcium carbonate in the samples of the materials.