-The ESR spin probe, TEMPAMINE +, was used to study the interlamellar behavior of adsorbed organic cations on hectorites solvated with water, ethanol, and water-ethanol mixtures, and saturated with several monovalent and divalent metallic cations. The mobility and orientation of the probe was affected greatly by the solvent, and to a lesser extent by the predominant exchangeable cation on the s...

In this study, three raw Brazilian clays from Joao Pessoa, Paraiba State (Aco AP, AVL and Verde Lodo) were characterized before after purification acid activation. Several instrumental techniques used, the classified as dioctahedral smectites with different compositions, where sample had highest content of montmorillonite. addition, analyses showed modification in clay mineral mainly due to rem...

Introduction: The primary target for the Mars Science Laboratory (MSL) rover investigation in Gale Crater is the 5 km thick stack of layers that make up the central mound of the crater, known officially as Aeolis Mons and informally as Mt. Sharp [1,2]. Previous near-infrared spectral investigations using the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) have shown that the northw...

-X-ray powder diffraction (XRD) patterns for many interstratified mica/glycolated smectites were calculated by changing combinations of probabilities and transition probabilities of two-component layers. Three basal XRD reflections, 5.1L7.6~ (P l), 8.9 ~ 0.2~ (P2), and 16.1~176 (P3) were selected for the quantification curves. A distinct relationship exists between a20~ (p2 Pl) and A202 (P3 -P2...

A variety of polycyclic aromatic hydrocarbons (PAHs) are reported in carbonaceous chondrites (CCs) and the interstellar medium (ISM). Although PAHs CCs not as large those detected ISM, their carbon isotope composition is interpreted pinpointing an origin. In contrast, hydrogen can be related to extent secondary processes, proportion alkylated within CCs. Here, we experimentally investigate mole...

Previous studies show that NH~ bearing 2:1 clays have two types of ammonium vibrational spectra. The first one, mainly observed for KBr pellets of NH4-smectites, gives absorption bands at 3150, 3020, 2840 and 1400 cm -~ (Petit et al., 1998). These NH~ bands, observed in the 1R spectra of many NH4 salts, correspond to vibrations of NH~ ions in the tetrahedral symmetry group (Nakamoto, 1963). Acc...