Nine muscovite samples from different localities were analysed for all major chemical elements and examined by infrared spectroscopy in the range of 4000–250 cm−1. Iron in the octahedral positions was found to cause an intensity decrease and shifting of some absorption bands. Other structural cations were found not to be effective in producing intensity and frequency changes due to the narrow variations in their amounts. Heating studies indicated that at about 800°C muscovite transforms into a dehydroxylated phase which is stable at least up to 1000°C. Particle size studies showed that 5 µm is the upper size limit for a representative spectrum.

L'étude de l'adsorption des α amino-acides à leur point isoélectrique par la montmorillonite saturée en cations minéraux de valences différentes montre que la quantité fixée dépend de la réactivité de l'acide aminé pour le cation minéral saturant la smectite. La fixation des α amino-acides est plus forte avec les cations bivalents qu'avec les cations monovalents; elle s'accompagne d'une libération des cations minéraux (échange).

Nous avons pu mettre en évidence l'existence de relations linéaires entre les quantités d'amino-acide fixé et les quantités de cations incorporés dans le minéral. Ces relations permettent de connaître à priori le comportement d'un acide aminé donné vis-à-vis de la montmorillonite saturée en un cation donné. Elles permettent de classer les amino-acides en trois familles: (1) les amino-acides qui sont incorporés sous une forme cationique simple par échange d'ions; (2) les amino-acides qui forment des sels et/ou des complexes de coordination avec les cations métalliques; (3) les amino-acides qui présentent un comportement compliqué et dont l'incorporation dans la smectite se conjugue avec une polycondensation.

Imogolite has been identified in small amounts in clays from a soil profile developed on pyroclastics of tephrite-bassanite composition. The major part of the fine clay was an allophanic material termed proto-imogolite, characterized by an infrared spectrum with some of the features given by imogolite, including a well-developed band at 346 cm−1. Similar products have been obtained in the laboratory.

Pour les hydrates à ‘deux couches’ des vermiculites issues des phlogopites 1 M, saturées par Li, Na, Ca, Mg ou Ba, nous avons rencontré quatre modes d'empilement des feuillets. Un seul (VIII) présente une structure ordonnée tridimensionnellement. Les trois autres (VI, VV et VVII) sont des structures semi-ordonnées.

Nous avons défini les translations entre feuillets pour chaque empilement ainsi que les domaines d'existence en fonction du cation et de l'humidité relative.

Pour l'édifice ordonné VIII calcique la structure de la couche interfoliaire est décrite (deux types de polyèdres d'eau plus de l'eau de liaison entre polyèdres).

Les diffèrents facteurs conditionnant, pour une vermiculite donnée, le ‘choix’ d'un mode d'empilement sont discutés : facteurs propres à la couche interfoliaire (nature des cations et degré d'hydratation); facteurs propres au feuillet (densité et localisation des charges, disposition des oxygènes de surface); facteurs liés à la texture.

Three samples have been selected to represent the sedimentary variations of the Basin of Autun. IR and ESR techniques have been used to study the sheet composition of the different kinds of clays. The kaolinites are fire clays with two different degrees of crystallinity. The illites have a muscovite origin and belong to the 1 M polytype with mainly tetrahedral Al3+ and Fe3+ substitutions but also with some octahedral Fe3+ substitutions. The dioctahedral phyllosilicates contain mostly divalent and trivalent octahedral substitutions.

This paper describes reactions occurring between the 25.5 Å ammonium propionate (AP) intercalate of a well-crystallized Georgia kaolinite with ethylene glycol, 1-6-diaminohexane and a quaternary amine (QA), namely

An ethylene glycol kaolinite complex is obtained with a strong d001 reflection at 10.9 Å. Seven 00l orders are observed easily. The IR spectrum shows bands at 3697, 3654 (weak shoulder) 3644 and 3622 cm−1, assigned to OH stretching of kaolinite and a strong OH band of E.G. at 3300 cm−1. No absorption band of AP is observed.

The 1.6-diaminohexane product is characterized by two broad reflections at 16.6 and 7.4 Å. Distinct Amide I and Amide II IR bands imply that the carboxyl group of the propionic acid has reacted with the amino group. By treating the AP complex with QA a very stable kaolinite-QA complex suspension in benzene was obtained. On drying an X-ray amorphous solid with no reflection at spacing & 20 Å was obtained. The hydroxyl stretching bands of the original kaolinite are drastically modified, a very strong band at 3560 cm−1, a strong doublet at 3620 and 3605 cm−1 were observed. A weak singlet is obtained at 3695 cm−1. The two OH bending bands are replaced by a single band at 912 cm−1. A complicated set of interactions results in the loss of stacking order about the C-axis, accompanied by some curling of layer packets. A prolonged treatment with water restores the X-ray and IR spectra of the original kaolinite.

Se estudia el efecto de la deshidratación sobre la superficie especifica y distribución del tamaño de poro en sepiolita y palygorskita. Se emplean las técnicas de A.T.D., A.T.G., adsorción-desorción de nitrógeno y microscopía electrónica.

La eliminación del agua higroscópico-zeolitica incrementa en los dos minerales la superficie especifica y la proporción de microporos accesibles a las moléculas de nitrógeno.

Con la pérdida del agua de cristalización disminuye, en ambos minerales, la superficie especifica y la proporción de los citados microporos, desapareciendo los de anchura inferior a 7 Å en las próximidades de la eliminación completa de esta clase de agua.

La eliminación del agua de constitución origina neuvos descensos de la superficie especifica en la sepiolita de acuerdo con las alteraciones sufridas, puestas de manifesto en al análisis térmico; más acusadas que en la palygorskita.

The reaction of ammonia with Mg-saturated vermiculite and hydrobiotite was studied by chemical analysis, X-ray diffraction, and differential thermal analysis, and the hydrobiotite also by infrared spectroscopy. The experimental evidence indicates that ammonia is adsorbed mainly as the ammonium ion, formed partly by reaction with interlayer water and partly by reaction with protons dissociated from octahedral layer hydroxyl groups, giving a single sheet of ions and molecules with irregular interlayer spacing. With large flakes (0.5–1.0 mm) the adsorbed ammonia is strongly retained on heating or on rehydration with water vapour: smaller flakes lose ammonia more readily. Ammonia uptake is related quantitatively to cation exchange capacity with two vermiculites and three hydrobiotites, and to the water content prior to adsorption.

Na-saturated vermiculite adsorbs a similar amount of ammonia to the Mg form, but it is mostly desorbed on rehydration. Cu-saturated vermiculite displays intermediate behaviour, with much of the ammonia initially present as a Cu-ammine which slowly reacts to give more ammonium ion.