The influence of some naturally occurring minerals on the precipitation of calcium carbonate polymorphs

Abstract In nature, calcium carbonate (CaCO3) in the form of calcite and aragonite nucleates through different pathways including geogenic and biogenic processes. It may also occur as pyrogenic lime plaster and laboratory-precipitated crystals. All of these formation processes are conducive to different degrees of local structural order in CaCO3 crystals, with the pyrogenic and precipitated forms being the least ordered. These variations affect the manner in which crystals interact with electromagnetic radiation, and thus formation processes may be tracked using methods such as X-ray diffraction and infrared spectroscopy. Here we show that defects in the crystal structure of CaCO3 may be detected by looking at the luminescence of crystals. Using cathodoluminescence by scanning electron microscopy (SEM-CL) and laser-induced fluorescence (LIF), it is possible to discern different polymorphs and their mechanism of formation. We were thus able to determine that pyrogenic calcite and aragonite exhibit blue luminescence due to the incorporation of distortions in the crystal lattice caused by heat and rapid precipitation, in agreement with infrared spectroscopy assessments of local structural order. These results provide the first detailed reference database of SEM-CL and LIF spectra of CaCO3 standards, and find application in the characterization of optical, archaeological and construction materials.

Download Full-text

The effect of different amino acids on spontaneous precipitation of calcium carbonate polymorphs

Journal of Crystal Growth ◽

10.1016/j.jcrysgro.2018.01.023 ◽

2018 ◽

Vol 486 ◽

pp. 71-81 ◽

Cited By ~ 14

Author(s):

Lara Štajner ◽

Jasminka Kontrec ◽

Branka Njegić Džakula ◽

Nadica Maltar-Strmečki ◽

Milivoj Plodinec ◽

...

Keyword(s):

Amino Acids ◽

Calcium Carbonate ◽

Calcium Carbonate Polymorphs

Download Full-text

X-Ray Diffraction Analysis of the Calcium Carbonate Polymorphs

Advances in X-ray Analysis ◽

10.1154/s0376030800008260 ◽

1970 ◽

Vol 14 ◽

pp. 29-37 ◽

Cited By ~ 2

Author(s):

S. T. Silk ◽

S. Z. Lewin

Keyword(s):

Calcium Carbonate ◽

Size Distributions ◽

X Ray Diffraction ◽

Particle Size Distributions ◽

Ray Method ◽

X Ray ◽

Packing Efficiency ◽

Integrated Intensities ◽

Packing Effect ◽

Calcium Carbonate Polymorphs

AbstractIt is shown that the integrated intensities of diffraction lines from calcite and aragonite powders prepared by precipitation vary markedly, due to variations in sample packing efficiency arising from different degrees of polydispersity in the particle size distributions. Since prolonged grinding to equalize initially divergent distributions changes the polymorph composition, the packing effect imposes the principal limitation on the precision of the x-ray method for certain types of calcium carbonate preparations.

Download Full-text

Studies of the Uroporphyrins

Clinical Chemistry ◽

10.1093/clinchem/6.2.71 ◽

1960 ◽

Vol 6 (2) ◽

pp. 71-97 ◽

Cited By ~ 4

Author(s):

C J Watson ◽

M H Berg ◽

V E Hawkinson ◽

Irene Bossenmaier

Keyword(s):

Calcium Carbonate ◽

Ethyl Acetate ◽

Extraction Procedure ◽

Type I ◽

Acute Porphyria ◽

Preliminary Heating ◽

Type Iii ◽

Naturally Occurring ◽

Isomer Composition ◽

Metabolic Significance

Abstract 1. Seventeen cases of hepatic porphyria have been studied with respect to variations in isomer composition of the urinary Waldenström uroporphyrin complex. 2. Comparison was made of the effect of various isolation procedures on the isomer composition of the uroporphyrin complex, with special reference to the effect of preliminary heating of the urine. 3. Methods not employing heat, including the ethyl acetate extraction procedure of Waldenström, the talc adsorption of Grinstein et al., and a number of modifications, usually yielded relatively small amounts of a uroporphyrin complex, preponderantly Type I isomer. In two instances, however, the complex contained 60-70 per cent Type III. When separable on calcium carbonate, the Type III component was again shown to consist in the main of a 7-COOH porphyrin. Preheating of the urine regularly produced much larger amounts of a Waldenström type porphyrin, and larger proportions of Type III isomer in the complex. 4. The Waldenström porphyrin isolated following conversion of naturally occurring porphyrinogen, by irradiation with ultraviolet light, usually contained a marked preponderance of uroporphyrin I. In certain instances, however, the porphyrinogen was entirely that of the "208" Type III porphyrin. 5. While the large amount of Type III porphyrin found after heating the urine undoubtedly represents nonenzymatic conversion of porphobilinogen, the smaller amount of Type I isomer usually present in major proportion in the preformed uroporphyrin complex or its porphyrinogen may have intrinsic metabolic significance. In exceptional cases of acute porphyria, the uroporphyrin of the unheated urine is preponderantly the Type III isomer.

Download Full-text

Natural Compounds as Sustainable Additives for Biopolymers

Polymers ◽

10.3390/polym12040732 ◽

2020 ◽

Vol 12 (4) ◽

pp. 732 ◽

Cited By ~ 5

Author(s):

Nadka Tzankova Dintcheva ◽

Giulia Infurna ◽

Marilena Baiamonte ◽

Francesca D’Anna

Keyword(s):

Calcium Carbonate ◽

Short Review ◽

Natural Compounds ◽

Natural Source ◽

Vegetable Fibers ◽

Naturally Occurring ◽

Alumino Silicate ◽

Sustainable Materials ◽

Application Fields

In the last few decades, the interest towards natural compounds, coming from a natural source and biodegradable, for biopolymers is always increasing because of a public request for the formulation of safe, eco-friendly, and sustainable materials. The main classes of natural compounds for biopolymers are: (i) naturally occurring fillers (nFil), such as nano-/micro- sized layered alumino-silicate: halloysite, bentonite, montmorillonite, hydroxyapatite, calcium carbonate, etc.; (ii) naturally occurring fibers (nFib), such as wood and vegetable fibers; (iii) naturally occurring antioxidant molecules (nAO), such as phenols, polyphenols, vitamins, and carotenoids. However, in this short review, the advantages and drawbacks, considering naturally occurring compounds as safe, eco-friendly, and sustainable additives for biopolymers, have been focused and discussed briefly, even taking into account the requests and needs of different application fields.

Download Full-text

The synthesis of copper/zinc solid solutions of hydroxyl carbonates, sulphates, nitrates, chlorides and bromides

Mineralogical Magazine ◽

10.1180/minmag.2011.075.5.2573 ◽

2011 ◽

Vol 75 (5) ◽

pp. 2573-2582 ◽

Cited By ~ 3

Author(s):

C. H. Yoder ◽

R. W. Schaeffer ◽

P. McWilliams ◽

A. Rowand ◽

X. Liu ◽

...

Keyword(s):

Calcium Carbonate ◽

Solid Solutions ◽

Copper Nitrate ◽

Zinc Nitrate ◽

Cell Parameters ◽

Naturally Occurring ◽

Jahn Teller ◽

Jahn Teller Effect ◽

Copper Zinc ◽

Temperature Preparation

AbstractThe relative stabilities of the copper/zinc solid solutions of hydroxyl sulphates, carbonates, nitrates, chlorides and bromides were studied by attempting their preparation using a variety of methods. All of the naturally occurring solid solutions except rosasite were obtained as single phases. Rosasite crystallized in a mixture with malachite and calcium carbonate during a room temperature preparation from calcium carbonate, copper nitrate and zinc nitrate. The solid solution with the antlerite stoichiometry [endmember Cu3SO4(OH)4] as well as the nitrates were not produced by the methods employed. All of the natural polymorphs of Cu2(OH)3Cl were obtained and a new method for the preparation of botallackite is reported. Botallackite was found to be stable in solution for over a year, contrary to previous reports. A bromine-bearing analogue of botallackite was prepared. Compounds were characterized by X-ray diffractometry, which was used to determine the unit-cell parameters, and by atomic absorption spectroscopy. The relative instability of solid solutions with certain stoichiometries is discussed in terms of the Jahn-Teller effect and relative solubilities.

Download Full-text