Dihydrogen Phosphate and Hydrogen Sulphate of 1,4-Dimethyl-1,4-diazabicyclo[2.2.2]octane-1,4-diium: Crystal Structures, Hydrogen Bonding and Infrared Spectra

Abstract  

The crystal structures of the title compounds consist of 1,4-dimethyl-1,4-diazabicyclo[2.2.2]octane-1,4-diium cation [C₈H₁₈N₂]²⁺ and [H₂PO₄]⁻ or [HSO₄]⁻ anions. Both crystal structures are monoclinic, the structure of the dihydrogen phosphate (I) is non-centrosymmetric (P2₁) with a = 6.4090(2) ?, b = 13.6920(5) ?, c = 7.6140(3) ?, β = 94.620(2)°, V = 665.97(4) ?³, Z = 2; whereas the unit cell of the hydrogen sulphate (II) is centrosymmetric (P2₁/c) with a = 13.8460(2) ?, b = 12.6610(2) ?, c = 8.0360(2) ?, β = 99.5800(12)°, V = 1389.10(5) ?³, Z = 4. Both the structures are formed by the different bonding patterns of the anions interlinked by strong and moderate O–H···O hydrogen bonds. While the structure of (I) consists of a two-dimensional network of the hydrogen bonded dihydrogen phosphates, the infinite chains of the hydrogen bonded hydrogen sulphates are the basic building unit of the structure (II). In addition to the dominant electrostatic interaction the divalent cations stabilize themselves in the structures by forming several C–H···O hydrogen bonds to the oxygen atoms of the anions. The IR spectra of both the compounds are strongly affected by the hydrogen bonds whose influence on OH stretching vibrations is analysed by means of the DFT calculations in the solid state.     

Using of Taguchi Method for Experimental Design of Crystallization Processes of an Oxidant: Tetraethylammonium Chlorochromate (VI)

Abstract  Crystallization of tetraethylammonium chlorochromate (C₂H₅)₄N[CrO₃Cl], TEACC, with desirable particle size as a performance characteristic was used to illustrate the design procedure. Taguchi design of experiments (DOE) method has been used for to plan a minimum number of experiments and optimization of crystallization processes. Four factors, which influence the crystal size, crystal growth and nucleation, were chosen. These factors are concentration, temperature, type of solvent and method of crystallization. After optimization the results show that concentration is most effective factor that has largest percent of contribution 53.26% and type of solvent is least effective factor that has smallest percent of contribution 4.33%. The optimum conditions are vapor diffusion as method, 0.043 g/15 mL for concentration, 0 °C for temperature and acetonitrile as solvent. These conditions must be produced suitable crystals for single crystal X-ray diffraction experiment. These results confirmed by experimental data and the crystals of the optimum conditions found to have suitable properties for single crystal X-ray diffraction. These crystals had sent for single crystal X-ray diffraction and diffraction data gathered successfully. A red block crystal was mounted on a glass fiber. The X-ray data determined monoclinic system, space group C2(#5), with a = 12.023(3), b = 7.998(2), c = 14.527(4) ?, β = 114.187(4)°, V = 1274.4(6) ?³ and Z = 4. Index Abstract  The Taguchi design of experiments (DOE) method has been used for to plan a minimum number of experiments and optimization of crystallization processes. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

[KCl<Subscript>3</Subscript>{H<Subscript>2</Subscript>dabco}]: A Unique 3-D Charge-Assisted Hydrogen-Bonded Hybrid Network of Anionic KCl<Subscript>3</Subscript> Chains and Organic Cations

Abstract  The 3-D hybrid network [KCl₃{H₂dabco}] resulted from the assemblage of KCl and [{H₂dabco}Cl₂] (1,4-diazabicyclo[2.2.2]octane) in H₂O. The compound crystallizes in the trigonal space group R-3c with a = b = 16.0437(2) Å, and c = 22.3094(2) Å. The structure consists in polymeric chains of anionic {KCl₃}²⁻ linked to {H₂dabco}²⁺ units by hydrogen bonds. Each organic cation establishes such charge-assisted H···Cl interactions with two inorganic arrays leading to a 3-D network. Index Abstract  Assemblage of KCl and [{H₂dabco}Cl₂] (1,4-diazabicyclo[2.2.2]octane) in H₂O resulted in a 3-D hybrid network of inorganic {KCl₃}²⁻ chains H-bonded to bridging organic cations.      

Simplex optimization of protein crystallization conditions

Simplex algorithms have been used to optimize for size, number and morphology of lysozyme and apoferritin crystals. This approach requires fewer experiments than the single-factor-at-a-time method or factorial designs and will be useful in conserving materials on the International Space Station. The simplex method has the possible advantage that it conserves on materials by reducing the number of experiments required to optimize a crystallization system. The process is iterative and exploratory and should allow optimum microgravity conditions to be determined which might very well be different from the optimum conditions on Earth. Because the simplex method uses simple mathematical operations to calculate the next set of crystallization conditions it will be easier for crystal growers to implement than factorial designs. Factorial experiments are based on varying all factors simultaneously at a limited number of factor levels. This results in a model that is used to determine the influence of each factor and their interactions. Factorial design experiments are especially useful at the beginning of an experimental study and as a screening tool to investigate a large number of factors. The simplex method is an optimization method which is model-independent and requires no fitting of models to data. Also, when applied to protein crystal growth the simplex method does not rely on an absolute quality score. Instead, with each iteration a comparison is made to the last experiment and the results are assigned as being “better or worse”. In this study, commercially obtained apoferritin was purified from 65% monomeric apoferritin to 92% monomeric apoferritin by size exclusion chromatography. Simplex optimization found the best apoferritin crystals were obtained at 15 mg/ml apoferritin, 2.0% CdSO₄, 25°C using the hanging drop vapor diffusion method of crystallization and at 24 mg/ml apoferritin, 1.5% CdSO₄, 25°C using the containerless crystallization method. For lysozyme, the simplex method found the best crystals at 19 mg/ml lysozyme, 7.0% (w/v) NaCl, pH 4.0, 25°C using the hanging drop vapor diffusion method of crystallization. For both proteins, the optimum conditions were found with less than ten experiments using very little protein. Finally, we report that the factors to be considered in the successful application of this method to crystallization are the number of variables to be studied, the initial conditions, step size and analysis of crystal quality.     

A new dabco templated metal sulfate, (C6H14N2)[Mn (H2O)6](SO4)2. Chemical preparation, hydrogen-bonded structure and thermal decomposition

The crystal structure of manganese sulfate templated by 1,4-diaza-bicyclo[2.2.2]octane (abbreviated dabco), (C₆H₁₄N₂)[Mn(H₂O)₆](SO₄)₂, was investigated using single crystal X-ray diffraction data. It crystallises in the monoclinic system (space group P2₁/c) with the following unit-cell parameters: a = 12.1392(2) ?, b = 12.3117(2) ?, c = 12.2765(2) ?, β = 104.607(1)°, V = 1775.47(5) ?³ and Z = 4. The structure has been solved using direct methods and refined by least-squares analysis [R ₁ = 0.0381, wR ₂ = 0.1082]. The crystal structure of the title compound is built from isolated [Mn(H₂O)₆]²⁺ octahedral cations, 1,4-diaza-bicyclo[2.2.2]octandiium cations (C₆H₁₄N₂)²⁺ and sulfate anions (SO₄)²⁻ connected by a three-dimensional hydrogen-bond network. The thermal decomposition of the precursor, studied by thermogravimetry and temperature-dependent X-ray powder diffraction, proceeds through four stages giving rise to the mixture of Mn₂O₃and Mn₃O₄. Supplementary Material CCDC 620298 contains the supplementary crystallographic data for this paper. These data can be obtained free of charge from The Cambridge Crystallographic Data Centre via www.ccdc.cam.ac.uk/data_request/cif.     

Synthesis, Crystal Structure and Characterization of a New Dabcodiium Hexaaquacobalt(II) Bis(Selenate), (C6H14N2)[Co(H2O)6](SeO4)2

Abstract  

The new hybrid material, cobalt selenate templated by 1,4-diazabicyclo[2.2.2]octane (abbreviated dabco), has been synthesised by the slow evaporation method at room temperature. Its crystal structure was investigated using single crystal X-ray diffraction data. It crystallises in the monoclinic system (space group P2₁/c) with the following unit-cell parameters: a = 12.9169(2) ?, b = 11.9101(2) ?, c = 12.4951(2) ?, β = 108.484(1)°, V = 1823.10(5) ?³ and Z = 4. The supramolecular structure of (C₆H₁₄N₂)[Co(H₂O)₆](SeO₄)₂ consists of isolated [Co(H₂O)]²⁺ and (C₆H₁₄N₂)²⁺ cations and (SeO₄)²⁻ anions linked together by three dimensional hydrogen-bond network. The infrared spectroscopy confirmed the presence of these different entities. The thermal behaviour of the precursor, studied by thermodiffractometry and thermogravimetric analyses, indicates that its decomposition proceeds through three stages giving rise to the cobalt oxide.     

The crystallization of lysozyme in the system of ionic liquid [BMIm][BF4]‐water

Lysozyme crystallization was conducted in the ionic liquid (IL) 1‐butyl‐3‐methylimidizolium tetrafluoroborate ([BMIm][BF₄]) with different buffer/IL proportions. It was found that the addition of [BMIm][BF₄] could promote the crystallization process, during which more lager single crystals with controllable morphologies could be obtained due to the manageable crystal growth velocity. A probable explanation was proposed based on the influence of the ionic polarization and kinetics in the lysozyme crystallization. Moreover, the transform in coordination number and the relative growth rate of different crystal faces were discussed. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Crystal structures of polymeric complexes of zinc(II) bromide and perchlorate with 1,4-diazoniabicyclo [2.2.2]octane-1,4-diacetate

Two zinc(II) complexes containing a flexible double betaine, namely [{Zn(L)Br₂}_n]·nH₂O (1) and [{Zn(L)₂(H₂O)₂}_n](ClO₄)_2n·4nH₂O (2) [L=1,4-diazoniabicyclo [2.2.2]octane-1,4-diacetate,⁻O₂CCH₂N⁺(CH₂CH₂)₃N⁺CH₂CO₂ ⁻], have been prepared and shown to have polymeric structures by single-crystal X-ray analysis. Complex (1) exhibits an infinite zigzag chain in which each zinc(II) atom is coordinated by two unidentate carboxylate oxygen atoms and two bromide ligands in a distorted tetrahedral geometry. Complex (2) consists of an assembly of catonic Zn(L)₂(H₂O)₂ ²⁺ moieties and discrete perchlorate anions as well as lattice water molecules. In (2) each zinc(II) atom is coordinated by two pairs of unidentate carboxylate oxygen atoms and two aqua ligands in a distorted octahedral geometry and cross-linked by skeletons of double betaine ligands to form a corrugated layer structure corresponding to the plane (100).     

Crystal structures of polymeric complexes of zinc(II) bromide and perchlorate with 1,4-diazoniabicyclo [2.2.2]octane-1,4-diacetate

Two zinc(II) complexes containing a flexible double betaine, namely [{Zn(L)Br₂}_n]·nH₂O (1) and [{Zn(L)₂(H₂O)₂}_n](ClO₄)_2n·4nH₂O (2) [L=1,4-diazoniabicyclo [2.2.2]octane-1,4-diacetate,^?O₂CCH₂N⁺(CH₂CH₂)₃N⁺CH₂CO₂ ^?], have been prepared and shown to have polymeric structures by single-crystal X-ray analysis. Complex (1) exhibits an infinite zigzag chain in which each zinc(II) atom is coordinated by two unidentate carboxylate oxygen atoms and two bromide ligands in a distorted tetrahedral geometry. Complex (2) consists of an assembly of catonic Zn(L)₂(H₂O)₂ ²⁺ moieties and discrete perchlorate anions as well as lattice water molecules. In (2) each zinc(II) atom is coordinated by two pairs of unidentate carboxylate oxygen atoms and two aqua ligands in a distorted octahedral geometry and cross-linked by skeletons of double betaine ligands to form a corrugated layer structure corresponding to the plane (100).     

Crystal Growth in Magnetic Fields (I) Crystallization of Me (NH4)2(SO4)2 · 6 H2O (Me = Zn,Cu, Ni,Fe) from Aqueous Solutions in Moderate Magnetic Fields

There are several reports in the literature concerning the study of the influence of magnetic fields on nucleation and crystal growth. Because of the partially opposite findings, the question whether the application of magnetic fields especially for mass crystallization processes may be of advantage has not been cleared yet. Therefore, the displacement rates of [110] and [001] single crystal faces of four Tutton's salts Me(NH₄)₂(SO₄)₂ · 6 H₂O (Me = Zn, Cu, Ni, Fe) from supersaturated aqueous solutions in a transversal direct magnetic field (B ≦ 1.4 T) has been measured and compared. Within the detection limit no reproducible effect was observed with Me = Zn, Cu, and Fe. A small growth acceleration occured in case of Ni(NH₄)₂(SO₄)₂ · 6 H₂O. The results which will be completed by measurements at higher magnetic flux densities, support the viewpoint that the application of magnetic fields on crystallization of diamagnetic substances from solutions offers no real advantage.     

Sodium Trihydrogen-1,4-Benzenediphosphonate: An Extended Coordination Network

Abstract  

Crystals of sodium trihydrogen-1,4-benzenediphosphonate, Na[H₃bdp], were prepared from the addition of aqueous sodium hydroxide to an acidified solution of 1,4-benzenediphosphonic acid (H₄bdp). These were shown by X-ray crystallography to crystallize in the space group P [`1] \bar{1} , with cell parameters a = 5.7500(3) ?, b = 7.9180(5) ?, c = 10.4420(6) ?, α = 80.398(3)°, β = 76.844(4)° and γ = 81.389(4)°. The crystal structure revealed that the title compound forms a coordination network in which sodium-phosphonate sheets are pillared by the benzene rings into a three-dimensional structure.     

The crystal and molecular structures of 3,3,6,6-Tetramethylbicyclo[2.2.1]heptane-2,5-dione and 6,6-Dibromo-1,3,3-Trimethylbicyclo[2.2.2] octane-2,5-dione

The X-ray crystal structures of two bicyclic diketones have been determined. 3,3,6,6-Tetramethylbicyclo[2.2.1]heptane-2,5-dione, C₁₁H₁₆O₂ (A), is monoclinic,C2/c (No. 15), with cell dimensionsa=9.071(3),b=9.748(5),c=12.322(6)Å,=110.15(3)°, andZ=4. The structure was determined by direct methods and refined toR ₁=0.065,R ₂=0.052 for 570 reflections. 6,6-Dibromo-1,3,3-trimethylbicyclo[2.2.2]octane-2,5-dione, C₁₁H₁₄Br₂O₂ (D), is orthorhombic,Pcab, (No. 61), with cell dimensionsa=11.206(3),b=18.818(6),c=11.695(4) Å, andZ=8. The structure was solved by the heavy-atom method and refined toR ₁=0.070,R ₂=0.065 for 1210 reflections. Bond lengths and angles within both structures do not differ from those in similar structures. The opening up of the internal ring angle of the ketone inA (vs. a normal bicyclo[2.2.1]heptane) and the consequent decrease of the adjacent internal ring angle brings the ketone carbon atoms nearer to the hydrogen atoms of the bridging methylene group.     

Crystallization kinetics of the Zr61Al7.5Cu17.5Ni10Si4 alloy using isothermal DSC and TEM observation

The crystallization behavior and microstructure development of the Zr₆₁Al_7.5Cu_17.5Ni₁₀Si₄ alloy during annealing were investigated by isothermal differential scanning calorimetry, X-ray diffractometry and transmission electron microscopy. During isothermal annealing of the Zr₆₁Al_7.5Cu_17.5Ni₁₀Si₄ alloy at 703 K, Zr₂Cu crystals with an average size of about 5 nm were first observed during the early stages (30% crystallization) of crystallization by TEM. The Zr₂Cu crystal size increased with annealing time and attained an average size of 20 nm corresponding to the stage of 80% crystallization. In addition, the change in particle size with increasing annealing time exhibited a linear relationship between grain growth time and the cube of the particle size for the Zr₂Cu type crystalline phase. This indicates that the crystal growth of the Zr₆₁Al_7.5Cu_17.5Ni₁₀Si₄ alloy belongs to a thermal activated process of the Arrhenius type. The activation energy for the grain growth of Zr₂Cu is 155 ± 20 kJ/mol in the Zr₆₁Al_7.5Cu_17.5Ni₁₀Si₄ amorphous alloy. The lower activation energy for grain growth in compared to that for crystallization in Zr₆₅Cu₃₅ 440 kJ/mol crystal corresponds to the rearrangement of smaller atoms in the metallic glass, Al or Si (compare to Zr).     

2-(1-Methyl-1H-indol-3-ylmethylene)-1-aza-bicyclo[2.2.2] octan-3-one: Acid-catalyzed isomerization of the Z isomer to the E isomer

Crystals of (Z)-2-(1-methyl-1H-indol-3-ylmethylene)-1-aza-bicyclo[2.2.2]octan-3-one (I) were obtained from a condensation reaction of 1-methyl-1H-indole-3-carboxaldehyde with 1-aza-bicyclo[2.2.2]octan-3-one and subsequent crystallization of the product from methanol. The isomeric (E)-2-(1-methyl-1H-indol-3-ylmethylene)-1-aza-bicyclo[2.2.2] octan-3-one hydrochloride (II) was obtained by treating a methanolic solution of I with a 1M solution of hydrogen chloride diethyl ether, followed by crystallization of resultant product from methanol. Crystal data: I, is monoclinic, P2₁, a = 5.7440(10), b = 11.102(2), c = 10.708(2) Å, = 91.751(10)°, and V = 682.5(2) ų with Z = 2, for D _cal= 1.296 mg/m³ and II, is monoclinic, P2₁/c, a = 8.8510(2), b = 17.4990(5), c = 20.4300(5) Å, = 101.3620(12)°, V = 3102.26(14) with Z = 8, for D _cal= 1.316 mg/m³.     

Crystal growth of tin oxide nano-sheets in aqueous solutions and time variation of N2 adsorption characteristics

Nucleation and crystal growth of tin oxide were realized in aqueous solutions. Nano-sheet structures grew in the solutions containing SnF₂ at 90 °C to develop in-plane size and thickness gradually. Their color, size, morphology, crystal structure and N₂ adsorption property varied with progress of crystal growth. Color of powder changed from white to light yellow, light blown to light green particles with growth. XRD analyses clarified that single phase of SnO₂ was synthesized in the aqueous solutions without high temperature annealing. It is an advantage to conventional ceramic firing process. Growth curves of crystallite size were consistent with morphological observations using Field Emission Scanning Electron Microscopy FE-SEM. Development of sheet structure was caused by crystal growth of SnO₂. Large crystallite size perpendicular to (200) planes indicated that growth along c-axis was suppressed compared to a-axis. Anisotropic crystal growth resulted anisotropic shape of nano-sheets. Chemical composition of fluorine-doped SnO₂ nano-sheets was estimated to Sn : F = 1 : 0.06–0.12. BET surface area increased with crystal growth and reached to 85 m²/g. It gradually decreased with synthesis period. Growth of sheet structure along in-plane direction related to increase of surface area. Further growth in thickness increased volume of the sheets to cause decrease of surface area per weight. N₂ adsorption property strongly related to crystal growth and shape change of the nano-structures. The system has the advantage of morphology controllability of tin oxide nano-structure and low environmental load.     

Crystallization behavior during cooling and glass-forming ability of Al2O3-poor Li2O–Al2O3–SiO2 melts

The influence of K₂O/(MgO + K₂O) on some melt properties, including crystallization during cooling of melts and glass-forming ability, was investigated in the Li₂O–Al₂O₃–SiO₂ system with low Al₂O₃ content. The dependence of viscosity on K₂O/(MgO + K₂O) above 1000 °C showed a monotonic decrease due to the reduction of [MgO₄] concentration and the conductivity also decreased due to the larger ion radius of K. The temperature dependence of conductivity for all melts showed an abrupt change at one temperature due to crystallization in which temperature of crystallization decreases with increase of K₂O. The crystallization behavior near liquidus temperature was studied quantitatively by calculating the crystal volume fraction from apparent viscosity value. The glass-forming ability of the melts was discussed by using data related with viscosity and crystallization. Finally, it was suggested that the melts with K₂O/(MgO + K₂O) ? 0.75 have a good glass-forming ability.     

Kinetics of crystal growth of mirabilite in aqueous supersaturated solutions

The crystallization of sodium sulfate decahydrate (Na₂SO₄·10H₂O, mirabilite) from supersaturated solutions was investigated using stable supersaturated solutions seeded with mirabilite seed crystals. The experiments were done in batch, stirred reactors in which the supersaturated solutions were prepared either by dissolution of sodium sulfate anhydrous at 32 °C followed by cooling to 18 or 20 °C or by mixing equal volumes of equimolar ammonium sulfate and sodium hydroxide solutions at 20 °C. Inoculation of the solutions supersaturated only with respect to mirabilite with seed crystals was accompanied with temperature increase of the thermostated solution. Despite the fact that crystal growth was initiated with seed crystals, the process started past the lapse of induction times inversely proportional to the solution supersaturation. The rates of crystal growth were measured both from the temperature rise and from the concentration–time profiles, which were linearly correlated. The measured crystal growth rates showed a parabolic dependence on supersaturation at low supersaturations. For higher values this dependence changed to linear, a behavior consistent with the BCF spiral crystal growth model. The morphology of the crystals growing at 20 °C showed typical prismatic habit, while at 18 °C when crystallized from cooled sodium sulfate solutions changes in the crystal habit to a leaf like morphology were observed.     

Kinetics of crystal growth of germanium disulfide in Ge0.38S0.62 chalcogenide glass

The crystal growth kinetics of GeS₂ in Ge_0.38S_0.62 glass has been studied by Differential Scanning Calorimetry (DSC) and microsopy. The linear crystal growth kinetics of both high temperature α-GeS₂ and low temperature β-GeS₂ polymorphs has been observed over a relatively broad range of temperatures, i.e. 420 < T < 494 °C that correspond to viscosity of supercooled melt: 3 × 10⁹ > η > 8 × 10⁵ Pa s. It seems that 2D nucleated growth is the most probable mechanism of crystallization for high temperature α-GeS₂ under these conditions. However, there are significant deviations for this model for the crystallization of low-temperature β-GeS₂. This might indicate some changes in crystal-melt interfacial energy or break down of Stokes–Einstein relation in that particular case. At temperatures below 500 °C the temperature range of directly observed crystal growth overlaps with isothermal DSC measurements. In this case overall crystallization kinetics can be described by the Johnson–Mehl–Avrami (JMA) nucleation-growth model for kinetic exponent n ≅ 4. The value of activation energy of nucleation estimated from these experiments E_N = 434 kJ mol⁻¹ is comparable with the activation energy of viscous flow in supercooled Ge_0.38S_0.62 melt (E_η = 478 kJ mol⁻¹). A more complex eutectic crystallization involving both GeS₂ and GeS phases has been observed at higher temperatures. This process is probably associated with secondary nucleation and cannot be described by a simple JMA model.     

Temperature gradient controlled growth and optical properties of Er:BaY2F8 crystals

Single crystals of Erbium (Er) doped BaY₂F₈ have been obtained by the temperature gradient technique (TGT). No‐seed‐grown crystal of Er:BaY₂F₈, with the dimensions up to several centimeters, was obtained by self‐crystallization. The optimizations of various growth parameters were systemically investigated. The results indicated that the temperature gradient of 6‐7 K/mm and the cooling velocity less than 6 K/h were suitable for the crystal growth. The XRD data and the investigations on the growth striations by a stereo polarization microscope displayed that the [001] direction is the dominating direction for the crystal growth. The crystal grown by TGT often cracks along with the (100) plane, which is caused by the excessive decrease of the temperature during the crystal growth, for there is a rapid change in the thermal expansion curve of the BaY₂F₈ crystal in the temperature range from 800 °C to 900 °C. The spectral properties of Er:BaY₂F₈ single crystals have been studied and the effects of frequency up‐conversion of the crystals are reported. Spectral data suggest that the quality of Er:BaY₂F₈ crystal obtained by TGT method is good and the crystal has the potential application in laser devices. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Kinetic studies on the influence of temperature and growth rate history on crystal growth

Crystallization experiments of sucrose were performed in a batch crystallizer to study the effect of temperature and growth rate history on the crystal growth kinetics. In one of the growth methods adopted, the isothermal volumetric growth rate (R_V) is determined as a function of supersaturation (S) at 35, 40 and 45 ºC. In the other, crystals are allowed to grow at constant supersaturation by automatically controlling the solution temperature as the solute concentration decreased. Using the latter method R_V is calculated as the solution is cooled. The obtained results are interpreted using empirical, engineering and fundamental perspectives of crystal growth. Firstly, the overall activation energy (E_A) is determined from the empirical growth constants obtained in the isothermal method. The concept of falsified kinetics, widely used in chemical reaction engineering, is then extended to the crystal growth of sucrose in order to estimate the true activation energy (E_T) from the diffusion‐affected constant, E_A. The differences found in the isothermal and constant supersaturation methods are explained from the viewpoint of the spiral nucleation mechanism, taking into account different crystal surface properties caused by the growth rate history in each method. Finally, the crystal growth curve obtained in the batch crystallizer at 40 ºC is compared with the one obtained in a fluidized bed crystallizer at the same temperature. Apparently divergent results are explained by the effects of crystal size, hydrodynamic conditions and growth rate history on the crystallization kinetics of sucrose. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)