Crystal Analysis Research Articles

Green synthesis of Carica papaya mediated silver nanoparticles: Characterization, antibacterial activity, and bioelectricity generation for sustainable applications in nanotechnology

This study presents a sustainable method for synthesizing silver nanoparticles (Ag NPs) using green Carica papaya extract (CPE) as a reducing and stabilizing agent. The green synthesis minimizes environmental impact and utilizes bioactive compounds in Carica papaya (CP), offering an economical and sustainable alternative. The goal is to employ CPE for the eco-friendly synthesis of Ag NPs, followed by comprehensive characterization, antibacterial evaluation, cytotoxicity against brine shrimp, and examination of bioelectricity generation. Locally sourced CP was boiled in deionized water, then cooled and filtered twice. The bio-reduction of silver ions to Ag NPs was confirmed by a color change when 45 mL of 0.005 M AgNO3 was mixed with 5 mL of CPE. Characterization through UV–vis absorption spectrophotometry (UV), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), Field emission scanning electron microscopy (FESEM), Energy dispersive X-ray spectroscopy (EDX), Transmission electron microscopy (TEM), and Gas chromatography-mass spectrometry (GC–MS) analysis confirms the successful formation and consistent size distribution of Ag nanoparticles. CPE is a crucial reducing agent, as evidenced by a distinct UV-visible peak at 422 nm. X-ray crystal analysis verifies highly crystalline Ag NPs with a face-centered cubic lattice structure. The d-spacing values in SAED images are consistent with the results obtained from XRD. Antimicrobial effectiveness against Escherichia coli and Staphylococcus epidermidis is demonstrated. The study explores the bioelectricity generation potential of CPE-synthesized Ag NPs, indicating promising prospects for sustainable energy solutions. Preliminary experiments show the ability of the nanoparticles to catalyze bio-electrochemical reactions. This dual-benefit study underscores CPEs role in antibacterial properties and bioelectricity generation, laying the groundwork for further research in sustainable nanotechnology applicable to healthcare and energy sectors and contributing to the advancement of environmentally friendly technologies.

A Review: Graphene Photonic Crystal Fiber

Next-generation optical fibers with diverse operating mechanisms, high functionality, and a porous structure that may be designed are known as photonic crystal fibers, or PCFs. In the meantime, two-dimensional graphene, possessing incredibly unique characteristics, is a perfect material for optoelectronic and optical uses. Recently, many studies have been published based on the integration of graphene with PCFs to create a new graphene PCF (Gr-PCF). There hybrid fibers show outstanding light-mater interaction over a broad spectrum range. This review starts with general introduction about photonic crystal fiber and analysis of optical properties. This is followed by a Plasmonic PCF then Graphene and physico-chemical properties of graphene nanomaterials. The review primarily covers the introduction of graphene and PCFs with many Applications including Optics Communications and different physical sensors.

Exploring magnetic space groups of [formula omitted] MXene and its connection to vibrational and electronic properties

The vibrational, electronic, and magnetic properties of two-dimensional Cr2N MXene were investigated. Two crystal cells (hexagonal and monoclinic) were considered with their respective magnetic space groups. In the absence of experimental data to fine-tune the Ueff (Hubbard correction), we utilized cell parameters and magnetic moment as a reference window, derived from meta-GGA calculations performed with the SCAN functional. A value of Ueff (1.25 eV) was determined, which does not overestimate the lattice parameters and magnetic moment values. Phonon scattering was calculated, and the vibrational modes were indexed. According to the density of states, the observed splitting in the eg and t2g orbitals, and the crystal field analysis, we deduce that chromium in the MXene Cr2N predominantly adopts an octahedral coordination environment, a combination of octahedral and tetrahedral coordination results in the splitting of the d orbitals. Finally, using Monte Carlo simulation, the critical temperature (Tc) for each space group with different functionals was obtained.

Zirconium-Based Metal-Organic Frameworks with Free Hydroxy Groups for Enhanced Perfluorooctanoic Acid Uptake in Water.

Perfluorooctanoic acid (PFOA) is a highly recalcitrant organic pollutant, and its bioaccumulation severely endangers human health. While various methods are developed for PFOA removal, the targeted design of adsorbents with high efficiency and reusability remains largely unexplored. Here the rational design and synthesis of two novel zirconium-based metal‒organic frameworks (MOFs) bearing free ortho-hydroxy sites, namely noninterpenetrated PCN-1001 and twofold interpenetrated PCN-1002,are presented. Single crystal analysis of the pure ligand reveals that intramolecular hydrogen bonding plays a pivotal role in directing the formation of MOFs with free hydroxy groups. Furthermore, the transformation from PCN-1001 to PCN-1002 is realized. Compared to PCN-1001, PCN-1002 displays higher chemical stability due to interpenetration, thereby demonstrating an exceptional PFOA adsorption capacity of up to 632mgg-1 (1.53mmolg-1), which is comparable to the reported record values. Moreover, PCN-1002 shows rapid kinetics, high selectivity, and long-life cycles in PFOA removal tests. Solid-state nuclear magnetic resonance results and density functional theory calculations reveal that multiple hydrogen bonds between the free ortho-hydroxy sites and PFOA, along with Lewis acid-base interaction, work collaboratively to enhance PFOA adsorption.

Experimental evidence supporting distinct adsorption configurations of N,N-bis(2‑hydroxy-3-chloropropyl) dodecylamine and dodecylamine on apatite surfaces: Quartz crystal microbalance and atomic force microscopy studies

In apatite flotation, a novel amine collector N,N-bis(2‑hydroxy-3-chloropropyl) dodecylamine demonstrates a considerably lower collecting ability than dodecylamine. Nonetheless, studies under identical dosage conditions reveal that the adsorption amounts of N,N-bis(2‑hydroxy-3-chloropropyl) dodecylamine on apatite surface surpass those of dodecylamine. The collecting efficiency of a collector is traditionally linked to its adsorption amount on the surface of a mineral, suggesting that a collector's efficacy increases with its adsorption amount. However, this study indicates that factors beyond adsorption amount significantly impact a collector's efficiency. Through first-principles calculations, it has been discovered that N,N-bis(2‑hydroxy-3-chloropropyl) dodecylamine and dodecylamine possess markedly varied adsorption configurations on apatite surfaces, implying that the variation grant them divergent collecting capabilities in apatite flotation. Supporting these findings, quartz crystal microbalance and atomic force microscopy analyses show the adsorption layer of dodecylamine is nearly triple thickness of N,N-bis(2‑hydroxy-3-chloropropyl) dodecylamine, with a notably different adsorption morphology. These results offer experimental validation of their differing adsorption configurations. This study not only strengthens the theoretical framework for developing selective control technologies of mineral flotation behaviors but also offers more perspectives for designing innovative collector molecules.

Non-doped blue-light emitting D–π–A type AIEE active novel quinoxaline derivatives and their application in acidochromism and data protection

This work reports on the synthesis of fluorescent dimethyl quinoxaline derivatives QXD1–QXD5. These D–π–A type organic blue-light emitters were fine-tuned by varying the electron donating strengths of donor (D) groups appended on quinoxaline acceptor (A) through a π-spacer. These compounds are emissive in both solid and solution states. This D–π–A arrangement resulted in intramolecular charge transfer (ICT), which led to positive solvatochromism. The analysis of single crystals of QXD1 and QXD3 revealed a twisted structure with herringbone packing arrangement. AIEE behavior could be seen in THF-H2O mixtures in these compounds. Adding trifluoroacetic acid (TFA) solution to these QXDs led to fluorochromic changes from blue to yellow fluorescence in solution, which was reversed upon adding triethylamine (TEA). A similar reversible fluorochromic change was observed upon the exposure of solid QXDs to TFA vapors, followed by TEA vapors. The distinguishable fluorocolorimetric responses of QXD3 and QXD4 towards TFA were employed for data protection through encryption and decryption.

Chromogenic recognition of Cr(III) and Cu(II) using a novel Schiff base and “turn-on” fluorescent detection of CO32− by its reduced scaffold in aqueous media

An upsurge of severe toxic inorganic ionic species in water arising due to anthropogenic activities, has caused global concern and detection of such harmful contaminants is a matter of supreme importance. In this regard, a novel trans-1,2-diaminocyclohexane containing Schiff base N,N′-di(4-acetamidophenylmethylene)-1,2-cyclohexanediamine (1) and its reduced scaffold N,N’-di(4-acetamidophenylmethyl)-1,2-cyclohexanediamine (2) have been synthesized and characterized by FT-IR and 1H & 13C NMR while the structures of both 1 and 2 have been determined by X-ray single crystal diffraction analysis. The detection response of 1 and 2 have been investigated toward same set of analytes and found to be entirely different both in absorption and emission studies. Compound 1 selectively and very sensitively detects Cr3+ and Cu2+via hydrolytic rupture of >C = N- bond as indicated by ratiometric change and emergence of an isosbestic point in UV–vis analysis. Further, the kinetic studies clearly suggested rapid hydrolysis of 1 (< 3.0 mins) in the presence of Cr3+ whereas it requires ∼1.0 h for complete hydrolysis with Cu2+. In contrast, the recognition of Cr3+ and Cu2+ not be observed through fluorescence technique. Moreover, 2 remains silent toward Cr3+/Cu2+in UV–vis analysis, however, it selectively recognizes CO32− through ‘turn-on’ fluorescence output in the background presence of several tested cations and anions. Job's plot and mass analysis suggested 1:2 (CO32−: 2) binding stoichiometry between CO32− and 2. Remarkably, the present findings demonstrate entirely different functionality of a Schiff base and its reduced form in presence of same analytes. The main objective of this report is to illustrate that how a subtle structural change of a molecule governs the analyte detection ability.

Early Palaeozoic affinity of Hainan Island to Gondwana: New clues from metamorphic monazite and titanite of the Baoban Complex

The Early Palaeozoic metamorphic records play a crucial role in determining the geological connection between Hainan Island and the Gondwana supercontinent. Nevertheless, the geochronological data for the Early Palaeozoic period is still sparse in Hainan Island. In this study, we conducted an integrated UPb geochronological and geochemical analysis of crystals from six monazite and three titanite samples obtained from the Mesoproterozoic Baoban Complex in the western region of Hainan Island. The mineral morphology and elemental compositions suggest that the examined monazite and titanite crystals exhibit characteristics typical of a metamorphic origin. Monazite and titanite UPb dating show two distinct metamorphic age populations: ca. 453–464 Ma and ca. 430–437 Ma. Our new data, combined with a comprehensive synthesis of metamorphic-magmatic ages from previous studies and other geological observations, offers crucial constraints on the palaeogeographic position and potential timing for the amalgamation of the micro-continents along the fringe of the Gondwana supercontinent. We suggest that Hainan Island was geologically connected to the Gondwana supercontinent during the Early Palaeozoic, a relationship that may have persisted until ca. 430 Ma. By this time, Hainan Island was probably closely linked to the South China and Indochina blocks.

Sugar-based synthesis of an enantiomorphically pure zeolite

Zeolites, well-known by their high selectivities in catalytic and separation processes due to their porous nature, play a crucial role in various applications. One significant long-term objective is the synthesis of enantiopure zeolites, potentially enabling enantioselective processes. Earlier attempts result in partial success, yielding some enantiomorphically enriched zeolites. In this study, we introduce a zeolite synthesis approach utilizing chiral organic structure directing agents (ch-OSDAs) derived from sugars, guiding the crystallization process toward achieving enantiomorphically pure S-STW zeolite. The purity of the zeolite is confirmed through extensive analyses of individual crystals using single-crystal X-ray diffraction, extracting Flack parameters and space groups. Theoretical and structural investigations confirm that the sugar-derived ch-OSDA perfectly fits the characteristic helicoidal channel of the zeolite structure, featuring its efficacy in achieving enantiopure zeolites.

Effect of phase content on deformation compatibility in ferrite and bainite dual-phase steel: experimental and crystal plasticity finite element analysis

Effect of phase content on deformation compatibility in ferrite and bainite dual-phase steel: experimental and crystal plasticity finite element analysis

Synthesis, crystal structure and anticancer activity of 4‑chloro-2-methoxybenzoic acid transition metal complexes

Seven novel transition metal complexes were synthesized from a starting material of 4‑chloro-2-methoxybenzoic acid, I: [Cu(4-Cl-2-MOBA)2(Py)2(H2O)2]; II: [Cu(4-Cl-2-MOBA)2(Imz)2]; III: [Co(4-Cl-2-MOBA)2(H2O)3.5]; IV: [Ni(4-Cl-2-MOBA)2(H2O)6]; V: [Ni(4-Cl-2-MOBA)2(DMF)]; VI: [Ni(4-Cl-2-MOBA)2(3-NH2–5-hypy)2(H2O)2O3.67] and VII: [Zn2(4-Cl-2-MOBA)3(4,4′-bipy)(Py)(HAc)]n by a one-pot, solvothermal method. All complexes were characterized by elemental analysis (EA), Fourier transform infrared spectroscopy (FTIR), ultraviolet-visible spectroscopy (UV–Vis), electrospray ionization mass spectrometry (ESI-MS) and single-crystal X-ray diffraction analysis (XRD). Single crystal XRD analyses showed that central metal ion type, auxiliary ligands and solvents acted synergistically to determine structural diversity. Complexes I-VII had cytotoxic activity towards the human tumor cell lines, A549 and SMMC-7721. Complex I showed the most potent cytotoxicity with an IC50 value of 8.976 μM for lung cancer cells and 13.94 μM for liver cancer cells.

Cu(II)‐Catalyzed Green Synthesis of 1,4,5‐Trisubstituted‐1,2,3‐Triazoles from Chalcone Derivatives – Studies on Their Cytotoxicity Profile

AbstractTriazoles are an important class of heterocyclic compounds due to their interesting structural features and versatile biological significance. In this regard, the present work highlights the synthesis of Cu(II)‐catalyzed 1,2,3‐trisubstituted triazoles through the cycloaddition of different chalcones with azides under neat methodology. A series of 16 triazole derivatives (3 a to 3 o) was prepared using 10 mol % Cu(II) complexes of 1,10‐phenanthroline and terpyridine‐based ligands as catalysts with moderate to excellent yields. All these derivatives were structurally analyzed by UV‐visible, infrared, 1H, 13C NMR and mass spectral data. The product, (4‐((4‐benzoyl‐5‐(4‐fluorophenyl)‐1H‐1,2,3‐triazol‐1‐yl) methyl)benzonitrile) (3 j) was structurally analyzed by single crystal XRD analysis. Also, the molecular structure of one of the catalysts, [Cu(Phen)2]2+(NO3−)2) was obtained by single crystal XRD analysis. Additional investigations of all these derivatives exhibited potential cytotoxic characteristics against MCF‐7 cancer cell lines. Among them, compounds 3 j, 3 i, 3 c, 3 d and 3 g facilitated the notable IC50 values. Moreover, the studies on the photophysical properties of synthesized derivatives showed the absorption bands in the range of 267–290 nm, depending on the nature of the substituent and the compounds 3 e and 3 f demonstrated the highest and lowest quantum yields as 0.05339 % and 0.01914 %, respectively.

Crystal field effects of Al doping on the Stark splitting and gain bandwidth of erbium doped silica fibers

In this study, erbium-doped silica fibers (EDFs) with different Al/Er ratios were prepared by high-temperature source combined with the modified chemical vapor deposition (MCVD) method. The effects of different Al/Er ratios on the gain performance of erbium-doped silica fiber amplifiers (EDFA) were investigated. The EDFA demonstrated in this paper achieves a maximum gain of 45 dB at 1560 nm when the signal power is −20 dB, while the bandwidth of 20 dB gain is up to 68 nm (1532∼1600 nm). Additionally, the effect of Al doping on the crystal field around the Er ion was analyzed and the Stark energy level distribution of the Er ions was further derived. Our approach offers a feasible solution for C + L band amplification from the perspective of Stark effect and crystal field analysis.

Spectrophotometric and chromatographic analysis of creatine:creatinine crystals in urine

Creatinine is the end product of the catabolism of creatine and creatine phosphate. Creatine phosphate serves as a reservoir of high-energy phosphate, especially in skeletal and cardiac muscle. Besides typical known changes in serum and urinary creatinine concentrations, rare cases associated with changes in serum and urinary creatine levels have been described in the literature in humans. These cases are mostly linked to an excessive intake of creatine ethyl ester or creatine monohydrate, often resulting in increased urine creatinine concentrations. In addition, it is known that at such elevated creatinine concentrations, creatinine crystallisation may occur in the urine. Analysis of crystals and urinary concrements, often of heterogenous chemical composition, may provide diagnostic and therapeutic hints to the benefit of the patient. The aim of the present work was to analyze urine crystals of unclear composition with microscopic and spectroscopic techniques.On routine microscopic analysis of urine, a preliminary suspicion of uric acid or creatinine crystals was expressed. The crystals were of a cuboid shape and showed polarization effects in microscopy. The dried urine sample was whitish-orange in colour, odourless and dissolved well in water. Protein concentration in dry weight (DW) urine was about 0.3 mg/mg. The measured zinc content in the studied sample was approximately 660 µg/g DW sample and copper content was approximately 64 µg/g DW sample. A lead signal of around 10 µg/g DW sample was also observed. UV–Vis analysis showed a maximum creatine peak around 220 nm, compatible with the spectrum of creatinine with a maximum peak of 230 nm. Using HPLC technique, an extreme high ratio of creatine to creatinine of about 38 was measured, which led to the conclusion of the occurrence of rare creatine crystals in urine.

Trapping of isotropic droplets by disclinations in nematic liquid crystals controlled by surface anchoring and elastic constant disparity.

Linear defects such as dislocations and disclinations in ordered materials attract foreign particles since they replace strong elastic distortions at the defect cores. In this work, we explore the behavior of isotropic droplets nucleating at singular disclinations in a nematic liquid crystal, predesigned by surface photopatterning. Experiments show that in the biphasic nematic-isotropic region, although the droplets are attracted to the disclination cores, their centers of mass shift away from the core centers as the temperature increases. The shift is not random, being deterministically defined by the surrounding director field. The effect is explained by the balance of interfacial anchoring and bulk elasticity. An agreement with the experiment can be achieved only if the model accounts for the disparity of the nematic elastic constants; the so-called one-constant approximation, often used in the theoretical analysis of liquid crystals, produces qualitatively wrong predictions. In particular, the experimentally observed shift towards the bend region around a +1/2 disclination core can be explained only when the bend constant is larger than the splay constant. The described dependence of the precise location of a foreign inclusion at defect cores on the elastic and surface anchoring properties can be used in rational design of microscale architectures.

The dual-transition-metal dichalcogenide monolayers anchored with Mn dimer: Promising electrocatalysts for efficient nitrogen reduction reaction

Due to its great efficiency, the electrocatalytic nitrogen reduction reaction (NRR) presents itself as a viable and eco-friendly substitute for the traditional Haber-Bosch ammonia production process. However, it is still a formidable task to find electrocatalysts with high activity and selectivity. In this study, a series of transition metals (TM = Ti–Ni, Zr–Mo, Ru–Pd, and Hf–Pt) anchored on 1T′-dual-transition-metal dichalcogenides (1T′-d-TMDs) monolayers (TM2@1T′-CrCoS4) were systematically investigated as electrocatalysts for NRR using first-principles calculations based on density functional theory. Based on a thorough examination of selectivity, high activity, and stability, Mn2@1T′-CrCoS4 and Co2@1T′-CrCoS4 demonstrate exceptional NRR performance. With a limiting potential of −0.11 V, Mn2@1T′-CrCoS4 stood out among them in terms of catalytic activity, favoring the enzymatic pathway. Furthermore, ab initio molecular dynamics (AIMD) simulations were used to assess the dynamic stability of Mn2@1T′-CrCoS4 and Co2@1T′-CrCoS4. To determine the source of increased activities, the density of states (DOS), charge density difference, and crystal orbital Hamilton population analysis were used. According to our research, the 1T′-d-TMDS is a viable substrate for the development of effective NRR catalysts and offers a platform for electrocatalyst experimentation.

Columnar Mesomorphism in a Methylthio-Decorated Triindole for Enhanced Charge Transport.

We report a semiconducting triindole-based discotic liquid crystal (TRISMe) functionalized with six p-methylthiophenyl groups at its periphery. While initially a crystalline solid at room temperature, TRISMe transitions to a columnar hexagonal mesophase upon heating and retains this supramolecular organization upon subsequent cooling, despite having only three flexible alkyl chains attached to the core's nitrogens. The incorporation of methylthio groups effectively hinders tight molecular packing, stabilizing the columnar arrangement of this disk-shaped molecule. Single crystal analysis confirmed the high tendency of this compound to organize into a columnar architecture and the role played by the methylthio groups in reinforcing such structure. The mesomorphic behavior of TRISMe provides an opportunity for processing from its molten state. Notably, our research reveals significant differences in charge transport depending on the processing method, whether solution drop-casting or melt-based. TRISMe shows hole mobility values averaging 3 × 10-1 cm2 V-1 s-1 when incorporated in diode-type devices from the isotropic melt and annealed at the mesophase temperature, estimated by SCLC (space-charge-limited current) measurements. However, when integrated into solution-processed organic field-effect transistors (OFETs), crystalline TRISMe exhibits a hole mobility of 3 × 10-4 cm2 V-1 s-1. The observed differences can be attributed to a beneficial supramolecular assembly achieved in the mesophase in spite of its lower order. These results emphasize the material's potential for applications in easy-to-process electronic devices and highlight the potential of methylthio moieties in promoting columnar mesophases.

Optimized Mn4+ doped Sr9Y2W4O24 perovskite for enhanced far-red-emitting luminescent material

In this study, a new perovskite Sr9Y2W4O24:Mn4+ is presented and its photoluminescence properties are examined in conjunction with electron paramagnetic resonance (EPR) analysis for comparison. Sol-gel synthesis resulted in a series of samples, that were characterized in detail using X-ray diffraction (XRD), Fourier Transform Infrared spectroscopy (FT-IR), diffuse reflectance spectrum (DRS), photoluminescence spectra (PL) and EPR. XRD patterns are consistent with standard data, affirming the tetragonal crystal arrangement of the synthesized samples. The band gap estimation based on DRS indicated a value of 5 eV. PL emission analysis identified a far-red emission peak (2Eg→4A2) at 677 nm, confirms the presence of Mn in the 4+ ionic state in the inorganic matrix. Crystal field analysis also demonstrated the presence of Mn4+ in a strong crystal field environment. Additionally, EPR analysis revealed distinct features of the observed broad line with a width of approximately 400 G and a six-line spectrum with g ∼1.98 characteristic of the Mn4+ doped Sr9Y2W4O24 perovskite. The prevailing evidence strongly suggests the likelihood of Mn4+ dopant ions occupying W6+ sites within the perovskite lattice. The EPR experimental data also confirmed the simulation data indicating the presence of Mn4+ ions in a given inorganic matrix. This investigation provides a comprehensive insight into the structural and spectroscopic properties of Mn4+ doped Sr9Y2W4O24 perovskites, confirming their potential as advanced lighting technologies to facilitate enhanced agricultural practices and plant cultivation.

Novel Insecticidal Butenolide-Containing Methylxanthine Derivatives: Synthesis, Crystal Structure, Biological Activity Evaluation, DFT Calculation and Molecular Docking.

The design of novel agrochemicals starting from bioactive natural products is one of the most effective ways in the discovery and development of new pesticidal agents. In this paper, a series of novel butenolide-containing methylxanthine derivatives (Ia-Ir) were designed based on natural methylxanthine caffeine and stemofoline, and the derivatized insecticide flupyradifurone of the latter. The structures of the synthesized compounds were confirmed via 1H-NMR, 13C NMR, HRMS and X-ray single crystal diffraction analyses. The biological activities of the compounds were evaluated against a variety of agricultural pests including oriental armyworm, bean aphid, diamondback moth, fall armyworm, cotton bollworm, and corn borer; the results indicated that some of them have favorable insecticidal potentials, particularly toward diamondback moth. Among others, Ic and Iq against diamondback moth possessed LC50 values of 6.187 mg ⋅ L-1 and 3.269 mg ⋅ L-1, respectively, - 2.5- and 4.8-fold of relative insecticidal activity respectively to that of flupyradifurone (LC50=15.743 mg ⋅ L-1). Additionally, both the DFT theoretical calculation and molecular docking with acetylcholine binding protein were conducted for the highly bioactive compound (Ic). Ic and Iq derived from the integration of caffeine (natural methylxanthine) and butenolide motifs can serve as novel leading insecticidal compounds for further optimization.

Enabling three-dimensional real-space analysis of ionic colloidal crystallization.

Structures of molecular crystals are identified using scattering techniques because we cannot see inside them. Micrometre-sized colloidal particles enable the real-time observation of crystallization with optical microscopy, but in practice this is still hampered by a lack of 'X-ray vision'. Here we introduce a system of index-matched fluorescently labelled colloidal particles and demonstrate the robust formation of ionic crystals in aqueous solution, with structures that can be controlled by size ratio and salt concentration. Full three-dimensional coordinates of particles are distinguished through in situ confocal microscopy, and the crystal structures are identified via comparison of their simulated scattering pattern with known atomic arrangements. Finally, we leverage our ability to look inside colloidal crystals to observe the motion of defects and crystal melting in time and space and to reveal the origin of crystal twinning. Using this platform, the path to real-time analysis of ionic colloidal crystallization is now 'crystal clear'.