Person:
Pina Martínez, Carlos Manuel

First Name

Carlos Manuel

Last Name

Pina Martínez

Affiliation

Universidad Complutense de Madrid

Faculty / Institute

Ciencias Geológicas

Department

Mineralogía y Petrología

Area

Cristalografía y Mineralogía

Identifiers

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Now showing 1 - 10 of 111

Malachite Crystallisation in a Diffusing-Reacting System
(Wiley-VCH Verlag, 1998) Astilleros García-Monge, José Manuel; Pina Martínez, Carlos Manuel; Fernández Díaz, Lurdes; López Andrés, Sol
The crystallisation of malachite has been studied in a system involving the counter diffusion of Cu2+ and CO3 through a silica gel column at 25 ºC. In such a system supersaturation is a function of time and position along gel column. Under these conditions kinetic variables are required in order to justify nucleation behaviour. Supersaturation rate has revealed as the most important parameter controlling nucleation features (waiting time, position of the precipitate, and metastability levels). The results presented here confirm the general nucleation behaviour reported by Prieto et al., (1989, 1991, 1994) for other carbonates. On the other hand, supersaturation changes during crystallisation process control the morphological evolution of malachite crystals.
In situ atomic force microscope observations of a dissolution– crystallisation reaction: The phosgenite– cerussite transformation
(Elsevier Science Ltd, 2000) Pina Martínez, Carlos Manuel; Fernández Díaz, Lurdes; Prieto Rubio, Manuel; Putnis, Andrew
The dissolution–reprecipitation reaction of phosgenite (Pb2Cl2CO3) to cerussite (PbCO3) has been observed in situ in a fluid cell of an atomic force microscope (AFM). The (001) face of phosgenite, in contact with static carbonated aqueous solutions, rapidly begins to dissolve. AFM observations show that dissolution occurs by generation and spread of square-shaped etch pits with sides parallel to (110) directions. The dissolution of the (110) steps is isotropic and the etch pits therefore remain square shaped during the dissolution process, as dictated by the existence of a fourfold axis perpendicular to the phosgenite (001) face. Two types of (110) etch pits were found: short-lived shallow pits, of one unit cell depth (8.8 Å), and deep pits, which rapidly reach depths between 10 and 60 nm. A few minutes after the dissolution begins, only the deep pits remain and subsequent dissolution of the phosgenite (001) surface proceeds by increasing their width and depth. The increase of Pb2+ and CO2-/3 concentration in the aqueous solution as a consequence of the dissolution sharply increases the supersaturation for PbCO3. As a result, after a certain incubation time, cerussite crystals nucleate on the phosgenite (001) surface and a coupled process of dissolution– crystallisation starts. Cerussite crystals, which grow by a spiral-growth mechanism, distort the concentration field around them. As a consequence, phosgenite dissolution is accelerated in the proximity of such growing cerussite individuals and both the formation of new deep etch pits and the development of irregular dissolution fronts are observed. Further phosgenite dissolution leads to an increase of cerussite nucleation and growth rates, in such a way that this dissolution– crystallisation phenomenon can be considered as an autocatalytic process.
High-resolution imaging of (100) kyanite surfaces using friction force microscopy in water
(Elsevier, 2015) Pimentel, Carlos; Gnecco, Enrico; Pina Martínez, Carlos Manuel
In this paper, we present high-resolution friction force microscopy (FFM) images of the (100) face of kyanite (Al2SiO5) immersed in water. These images show an almost rectangular lattice presumably defined by the protruding oxygen of AlO6 polyhedra. Surface lattice parameters measured on two-dimensional fast Fourier transform (2D-FFT) plots of recorded high-resolution friction maps are in good agreement with lattice parameters calculated from the bulk mineral structure. Friction measurements performed along the [001] and [010] directions on the kyanite (100) face provide similar friction coefficients μ ≈ 0.10, even if the sequences of AlO6 polyhedra are different along the two crystallographic directions.
Metastable phenomena on calcite {1014} surfaces growing from Sr2+–Ca2+–CO3 2- aqueous solutions
(Elsevier Science B.V., Amsterdam., 2003) Astilleros García-Monge, José Manuel; Pina Martínez, Carlos Manuel; Fernández Díaz, Lurdes; Putnis, Andrew
In situ atomic force microscopy (AFM) experiments, scanning electron microscopy (SEM) imaging and composition analysis, and X-ray diffraction have provided information about the growth, dissolution and transformation processes promoted by Sr2 + –Ca2 + –CO3 2 aqueous solutions in contact with calcite {101¯4} surfaces. Experiments have shown a wide variety of surface phenomena, such as the influence of the Sr-bearing newly-formed surface on the subsequent growth (template effect), the growth and subsequent dissolution of surfaces and the nucleation of secondary three-dimensional nuclei on calcite surfaces. These phenomena reveal the metastability of the crystallisation system and are a consequence of the interplay between thermodynamics (the relative stability of the two calcite and aragonite structure solid solutions that can be formed), supersaturation of the aqueous solution with respect to the two possible solid solutions, and the crystallographic control of the surfaces on cation incorporation.
Diseño de estructuras cristalográficas para impresoras 3D
(2021-05-31) Pina Martínez, Carlos Manuel; Crespo López, Ángel; Pimentel Guerra, Carlos; Cabeza Llorca, Ana; Ávila Brande, David; Castillo Martínez, Elisabeth; López-Acevedo Cornejo, María Victoria; Otero Díaz, Luis Carlos
Se propone el diseño de estructuras cristalográficas para impresoras 3D, utilizables en la enseñanza y divulgación de la Cristalografía, la Mineralogía y la Química. Estos modelos incluirán minerales, cuasicristales y poliedros de coordinación.
Friction and Wear of Mineral Surfaces in Liquid Environments
(Springer International Publishing Switzerland, 2015) Pina Martínez, Carlos Manuel; Pimentel Guerra, Carlos; Gnecco, Enrico; Gnecco, Enrico; Meyer, Ernest
Lateral Force Microscopy (LFM) is a very suitable technique to investigate the structure and reactivity of mineral surfaces in liquids. Studies performed in the last two decades have shown that the dissolution and growth of mineral surfaces immersed in water and aqueous solutions can be monitored by recording friction signals with LFM. Moreover, the sensitivity of lateral forces to both structure and chemistry makes possible to use LFM to obtain information about monolayers formed on mineral faces. Finally, numerous mineral surfaces are excellent substrates on which nanoparticles and complex organic molecules can be deposited and subsequently imaged and manipulated. This opens the way to future applications in molecular electronics. This chapter presents an overview of the recent use of LFM in liquid to investigate mineral surfaces and processes occurring on them.
Transformación de celestina en estroncianita a 25 ºC: generación de texturas y microporosidad
(Sociedad Española de Mineralogía, 2009-09) Pina Martínez, Carlos Manuel
A combined in situ AFM and SEM study of the interaction between celestite (001) surfaces and carbonate-bearing aqueous solutions
(Elsevier, 2007) Sánchez Pastor, Nuria; Pina Martínez, Carlos Manuel; Fernández Díaz, Lurdes
In this paper, we present in situ atomic force microscopy (AFM) observations of the interaction between celestite (SrSO4) (001) surfaces and Na2CO3 aqueous solutions. The observations indicate that the interaction is characterized by a rapid alteration (carbonatation) and dissolution of the original surface, shortly followed by the formation of a new phase. EDX analyses indicate that the new phase is strontianite (SrCO3). Its crystallization involves the formation and spreading of islands of about 2.75 nm in height, which chiefly occurs on the step edges of the dissolving celestite substrate. The thickness of the islands remains almost constant during their spreading, which occurs mainly parallel to the celestite [010] direction. As a result of the progressive coalescence of the islands, a fairly homogeneous epitaxial layer forms on the celestite (001) face. At the initial stages, the formation of islands on the celestite (001) faces enhances dissolution, indicating the existence of a coupling between dissolution and crystallization reactions. Our measurements on series of FM images provided quantitative information about coupled dissolution-growth rates on a nanoscale. The effect of the coupled reactions on the celestite (001) surface on a microscopic scale was also studied by scanning electron microscopy (SEM).
Molecular-scale shear response of the organic semiconductor β-DBDCS (100) surface
(American Physical Society, 2017) Álvarez-Asensio, Rubén; Moreno Ramírez, Jorge S.; Pimentel, Carlos; Casado, Santiago; Matta, Micaela; Gierschner, Johannes; Muccioli, Luca; Yoon, Seong-Jun; Varghese, Shinto; Park, Soo Young; Gnecco, Enrico; Pina Martínez, Carlos Manuel
In this work we present friction-force microscopy (FFM) lattice-resolved images acquired on the (100) facet of the semiconductor organic oligomer (2Z,2'Z) − 3,3'-(1,4-phenylene)bis(2-(4-butoxyphenyl)acrylonitrile) (β-DBDCS) crystal in water at room temperature. Stick-slip contrast, lateral contact stiffness, and friction forces are found to depend strongly on the sliding direction due to the anisotropic packing of the molecular chains forming the crystal surface along the [010] and [001] directions. The anisotropy also causes the maximum value of the normal force applicable before wearing to increase by a factor of 3 when the scan is performed along the [001] direction on the (100) face. Altogether, our results contribute to achieving a better understanding of the molecular origin of friction anisotropy on soft crystalline surfaces, which has been often hypothesized but rarely investigated in the literature.
Dolomite cation order in the geological record
(Elsevier Science B.V., Amsterdam., 2020-08-05) Pina Martínez, Carlos Manuel; Pimentel Guerra, Carlos; Crespo López, Ángel
Dolomite is a carbonate mineral frequently found in sedimentary rocks from Proterozoic to Holocene. In the Iberian Peninsula, dolomites appear in a wide number of geological formations and they can be considered as representative of dolomites crystallised in most (post)sedimentary environments on Earth. In this paper, we present a first systematic study of the cation order of dolomites formed from Neoproterozoic to late Holocene. We found that the lowest values of cation order (quantified by measuring I01.5/I11.0 intensity ratios on diffractograms) mainly correspond to dolomites formed in about the last 30 Myr. In contrast, older dolomites usually reach maximum I01.5/I11.0 intensity ratios. Furthermore, higher values of cation order seem to be related to higher values of the full width half maximum of 10.4 diffraction peaks (FWHM10.4). Assuming that a decrease in FWHM10.4 (i.e. an increase in the crystallite size) in sedimentary environments indicates mineral ripening, our results show that Mg-Ca ordering in dolomites might take place mainly by a dissolution-(re)crystallisation ageing process operating over large geological periods.