Hydrogen bonding in ikaite, CaCO<sub>3</sub>.6H<sub>2</sub>O

Swainson, I. P.; Hammond, Robert P.

doi:10.1180/0026461036730117

Cited by 33 publications

(39 citation statements)

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“…11 The neighbouring ion pairs are linked by hydrogen bonds only, which are temperature sensitive. 12 Therefore, ikaite is only stable at temperatures below 5°C and in the natural environment it is only found in cold seawater, deep-sea sediment, Fig. 1 (a) The evolution of pH and calcium activity (indicated by the measured potential from a calcium electrode) of the reaction solution.…”

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confidence: 99%

Reentrant phase transformation from crystalline ikaite to amorphous calcium carbonate

et al. 2018

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We report the spontaneous transformation of highly hydrated crystalline ikaite into less hydrated amorphous calcium carbonate (ACC), which has the outer contours of micrometer-sized crystals, a multi-level interconnected porous structure and a very high specific surface area (98.3 cm 2 g −1 ). 4 Here, we report that the opposite transformation from a crystalline calcium carbonate phase into ACC can also happen spontaneously. Solid state amorphization, a process where a crystalline phase transforms into an amorphous state, may happen through a large input of energy necessary for such an energetically "uphill" conversion of structures. A typical example is mechanical grinding of crystalline materials, which may lead to amorphous materials via generation of localized heating followed by quenching, via an increase in disorder or massive creation of defects. . The SEM images of ACC (d) and a sample during transformation (∼2400 s, ACC + ikaite) (e).

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confidence: 99%

Reentrant phase transformation from crystalline ikaite to amorphous calcium carbonate

et al. 2018

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“…Obviously, the calculated values are slightly greater than the results from the theoretical and experimental values. [7,14,15,20,21] In this work, the calculated lattice parameters by using PBE + TS functional are slightly different from those obtained by other methods such as B3LYP-D2 and PBE-D2. The discrepancy between the calculated value and the experimental value probably comes from lattice defects, the effect of temperature on crystal structure, experimental environment, and different approximation functions.…”

Section: Computational Methods and Detailsmentioning

confidence: 58%

“…Calcium carbonate hemihydrate (CaCO 3 Á1/2H 2 O) [8] has a monoclinic crystalline structure, belonging to the P121/c1 (14) space with lattice parameters a = 9.64 Å, b = 10.47 Å, and c = 6.42 Å. The structure of monohydrocalcite (CaCO 3 Á1H 2 O) [4,5] is selected as space group: P31(144) with lattice parameters a = 10.65 Å, b = 10.65 Å, and c = 7.64 Å.…”

Section: Computational Methods and Detailsmentioning

confidence: 99%

Investigation on the stability, electronic, optical, and mechanical properties of novel calcium carbonate hydrates via first‐principles calculations

Zhou

Liu

et al. 2020

Int J of Quantum Chemistry

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Calcium carbonate (CaCO3) is an inorganic compound which is widely used in industry, chemistry, construction, ocean acidification, and biomineralization due to its rich constituent on earth and excellent performance, in which calcium carbonate hydrates are important systems. In Zou et al's work (Science, 2019, 363, 396‐400), they found a novel calcium carbonate hemihydrate phase, but the structural stability, optical, and mechanical properties have not been studied. In this work, the stability, electronic, optical, and mechanical properties of novel calcium carbonate hydrates were investigated by using the first‐principles calculations using density functional theory. CaCO3·xH2O (x = 1/2, 1 and 6) are determined dynamically stable phases by phonon spectrum, but the Gibbs energy of reaction of CaCO3·1/2H2O is higher than other calcium carbonate hydrates. That is why CaCO3·1/2H2O is hard to synthesize in the experiments. In addition, the optical and mechanical properties of CaCO3·xH2O (x = 1/2, 1 and 6) are expounded in detail. It shows that the CaCO3·1/2H2O has the largest bulk modulus, shear modulus, and Young's modulus with the values 60.51 GPa, 36.56 GPa, and 91.28 GPa. This work will provide guidance for experiments and its applications, such as biomineralization, geology, and industrial processes.

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“…Ito (1998) investigated the transformation of natural ikaite to elucidate the environmental factors controlling the transformation kinetics. The quite anisotropic thermal expansion behavior of ikaite was observed clearly in neutrons and synchrotron X-ray powder diffraction studies (Swainson and Hammond, 2003;Lennie et al, 2004). The largest thermal expansion occurs along the crystallographic a-axis, whereas the smallest occurs along the b-axis (Lennie et al, 2004).…”

Section: Introductionmentioning

confidence: 84%

“…The calcium is coordinated by two oxygen atoms from carbonate, forming CaCO 3 , and by six oxygen atoms from water molecules (Lennie et al, 2004). The phase transformation of ikaite has been studied extensively using X-ray powder diffraction and Raman spectroscopy as a function of temperature, pressure, and time (Ito, 1998;Mikkelsen et al, 1999;Swainson and Hammond, 2003;Lennie et al, 2004;Lennie, 2005;Shahar et al, 2005;Tang et al, 2009). Ito (1998) investigated the transformation of natural ikaite to elucidate the environmental factors controlling the transformation kinetics.…”

Section: Introductionmentioning

confidence: 99%

Structural change induced by dehydration in ikaite (CaCO3·6H2O)

Tateno

Kyono

2014

Journal of Mineralogical and Petrological Sciences

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Dehydration-induced structural change in ikaite, CaCO 3 ·6H 2 O, is investigated using a low-temperature singlecrystal X-ray diffraction study. At −50°C, the crystal structure of ikaite is monoclinic, of space group C2/c with the unit cell parameters a = 8.8134 (1), b = 8.3108 (1), c = 11.0183 (1) Å, and β = 110.418 (1)°. The measurements were performed in 10°C steps, revealing a monotonous increase of unit cell volume from 756.3 to 758.0 Å 3 , up to −20°C. The unit cell volume then jumps to 771.0 Å 3 at −10°C. The unit cell expands anisotropically along the a-axis followed by the c-axis. The ikaite structure is finally lost at 0°C, which is a much lower temperature for decomposition than previously reported values. The low temperature decomposition is attributable to the aridity of the sample. The elongation of the O1-O4 intermolecular distance parallel to the (101) plane engenders the substantial increase in the a-axis and c-axis. The two-dimensional molecular sheets composed of the CaCO 3 ·6H 2 O molecules are stacked with hydrogen bondings along the c-axis. The expansion of the c-axis is affected by variations in the hydrogen bondings between the sheets. The intramolecular Ca-O2 and Ca-O5 bond lengths and the intermolecular O1-O5 distance are greatly elongated immediately before the decomposition of ikaite structure. These expansions along the b-axis, however, are offset by the increase in the O2-C-O2 bond angle in the CO 3 geometry, aligned perfectly parallel to the b-axis. The intermolecular angles are maintained as almost constant until the ikaite structure is lost. It can be concluded therefore that the movement of H 2 O molecules from the crystal lattice occurs simultaneously because the CaCO 3 ·6H 2 O molecules are stabilized by the hydrogen-bonding network immediately before dehydration.Keywords: Calcium carbonate hydrate, Decomposition, Phase transition, Low-temperature single-crystal X-ray diffraction INTRODUCTIONCalcium carbonates are abundant materials found in sedimentary rock throughout Earth's surface. During the past two decades, much research has been conducted on calcium carbonate nucleation, given that abiotic precipitation of calcium carbonate minerals constitutes a huge sink of CO 2 gas from the atmosphere, which directly affects the ocean chemistry, Earth's atmosphere, and climate (e.g., Archer and Maier-Reimer, 1994;Kleypas et al., 1999;Riebesell et al., 2000;Ries et al., 2009;Bodnar et al., 2013;Kaszuba et al., 2013). Calcium carbonate minerals occur naturally in six different modifications: three anhydrous crystalline polymorphs (CaCO 3 ) as calcite, aragonite, and vaterite; two hydrate phases as monohydrocalcite (CaCO 3 ·H 2 O) and ikaite (CaCO 3 ·6H 2 O); and amorphous calcium carbonate (ACC), which has similar stoichiometry to that of monohydrocalcite (LeviKalisman et al., 2002). Ikaite is a metastable mineral in the sedimentary realm formed naturally from aqueous solutions in near-freezing anoxic marine sediments (Zabel and Schulz, 2001;Greinert and Derkachev, 2004;Selleck et al.,...

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Hydrogen bonding in ikaite, CaCO₃.6H₂O

Cited by 33 publications

References 14 publications

Reentrant phase transformation from crystalline ikaite to amorphous calcium carbonate

Reentrant phase transformation from crystalline ikaite to amorphous calcium carbonate

Investigation on the stability, electronic, optical, and mechanical properties of novel calcium carbonate hydrates via first‐principles calculations

Structural change induced by dehydration in ikaite (CaCO3·6H2O)

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Hydrogen bonding in ikaite, CaCO3.6H2O

Cited by 33 publications

References 14 publications

Reentrant phase transformation from crystalline ikaite to amorphous calcium carbonate

Reentrant phase transformation from crystalline ikaite to amorphous calcium carbonate

Investigation on the stability, electronic, optical, and mechanical properties of novel calcium carbonate hydrates via first‐principles calculations

Structural change induced by dehydration in ikaite (CaCO3·6H2O)

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Hydrogen bonding in ikaite, CaCO₃.6H₂O