Gravimetric Determination Research Articles

Measuring Respirable Crystalline Silica (Quartz) from Powdery Materials through Sedimentation and X-ray Diffractometry

When possible, choosing materials with a low quartz content is the most effective and cost-efficient way to prevent the respirable quartz exposure of workers and other end users of powdery products. Therefore, methods are needed to analyze low amounts of quartz from powdery products, such as sand, gravel, plaster, cement, and concrete. To this end, we present a method to analyze respirable dust and quartz from powdered materials, such as construction products. The method includes separation of the respirable dust fraction by liquid sedimentation, followed by gravimetric analysis and determination of the crystalline silica content by X-ray diffractometry. While also aiding in the development of less harmful products, analysis of the quartz concentration of powdery products is statutory in Eu countries, excluding natural products not chemically modified. According to EU Regulation No. 1272/2008, products must be classified if they contain harmful substances in concentrations above 0.1 wt.%, and clauses pertaining to cancerous properties and harmfulness to lungs should be included. Also, mineral producers in the EU recommend that products containing respirable quartz should be labelled based on their quartz concentration, provided the concentration exceeds 1 wt.%. The present method meets these needs. The analysis can be performed in parallel from 50 to 1000 mg (dry weight) of powdery materials. The quantitative limit of determination was 10 µg per sample, corresponding to 0.01 wt.%, and the linear range 0.02–10 wt.% (10–5000 µg quartz per sample, Pearson correlation coefficient 0.99). The accuracy of the method was 82% and the repeatability 11%.

Effect of alkali metal salt addition on disintegration of titania particles precipitated from tetraethyl orthotitanate in ethanol

AbstractInline (or in situ) photon density wave spectroscopy was used to monitor the disintegration of secondary titania particles into their primary particles. Photon density wave spectroscopy can be applied to determine the reduced scattering coefficient of a dispersion without dilution or calibration, and thus enables process analysis in materials that are usually unsuitable for established particle characterization techniques. In this work, amorphous titania particles were precipitated from tetraethyl orthotitanate in ethanol by addition of water in presence of different alkali metal salts (NaCl, KCl, CsCl, K2SO4) with concentrations between 0 and 1.6 mM. The present results suggest that the synthesized titania secondary particles disintegrate into their primary particles if the electrostatic repulsion between the primary particles is promoted. This can be achieved by an increased alkali chloride concentration in the synthesis or by addition of larger alkali metal ions. In contrast, the particles are only weakly charged upon addition of sulfate ions, and the disintegration stops. The conclusions drawn from photon density wave spectroscopy results are supported by gravimetric determination of the particle yield, dynamic light scattering measurements, zeta‐potential measurements, and electron micrographs. Additionally, the disintegration was driven to completion by addition of hydrochloric acid to create a transparent suspension of titania primary particles as small as 4.7 nm.

Expounding protection mechanisms of ring charge density and ligand number for N-containing heterocyclic as corrosion inhibitors using experimental and calculation

Effect of ring charge density and ligand number on corrosion inhibition efficiency for N-containing compounds has not been systematically studied. Herein, the above factors were explored by comparison with pyridine (Py), quinoline (Ql) and 2,2′-bipyridine (By). Further, 4′-(4-aminophenyl)-2,2′:6′,2″-terpyridine (NH2-TPy) was synthesized to improve anti-corrosion ability. Gravimetric determination, electrochemistry, surface and solution analysis results showed that NH2-TPy demonstrated maximum protection efficiency of 95.37% with mixed inhibition mechanism. Theoretical calculation explained differences in protective capacity of N-containing heterocyclic compound by revealing possible anchoring sites and bonding strength. This study provides unique insights for design of new inhibitors and N-containing heterocyclic polymer.

Analysis of different combinations of gravity data types in gravimetric geoid determination over Bali

Abstract Following the Regulation of the Head of the Geospatial Information Agency (BIG) No. 13 of 2021, geoid is used as the Vertical Geospatial Reference System in Indonesia. Applications using the geoid as an ideal reference require a much higher accuracy and resolution than the geoid obtained from models derived solely from satellite data. The Indonesian Geospatial Information Agency considers the geoid ideal if it has reached an accuracy of better than 15 cm. Recent studies have combined satellite and other gravimetric data to produce a combined geoid model with increased resolution. Gravimetric data obtained from measurements close to the Earth’s surface, such as airborne and terrestrial gravity data, are particularly attractive because the high-frequency portion of the signal is more apparent and can contribute to the medium to high frequencies of the gravity field. This study models the geoid over Bali Island by combining satellite, airborne and terrestrial gravity data. Calculations were performed using Least Square Collocation (LSC) and Remove-Compute-Restore (RCR) techniques. The gravimetric geoid model was tested against the geometric geoid profile calculated from a GNSS/Levelling survey. The geoid, calculated by combining the GOCO06S satellite gravity model, the GGMplus gravity model and airborne gravity data at an average flight altitude of 4100 m produces a standard deviation of 14.46 cm along the 125 km validation path. After also adding terrestrial gravity data, the standard deviation increased to 16.37 cm. By comparison, the results of the validation of the geoid model from GOCO06S and INAGEOIDV2 with geometric geoids have standard deviation values of 79.56 cm and 16.40 cm, respectively. However, the results of the statistical tests are strongly influenced by the data quality used as validation, in this case, GNSS/Levelling. It is shown that the GNSS/Levelling data over Bali contains significant errors, which have been reduced based on an analysis of geometric vertical deflections. A geometric geoid profile with higher accuracy is required to test the accuracy of the gravimetric geoid models more reliably.

In vitro exposure to PM2.5 of olfactory Ensheathing cells and SH-SY5Y cells and possible association with neurodegenerative processes

PM2.5 exposure represents a risk factor for the public health. PM2.5 is able to cross the blood-alveolar and blood-brain barriers and reach the brain through three routes: nasal olfactory pathway, nose-brain pathway, blood-brain barrier pathway. We evaluated the effect of PM2.5 to induce cytotoxicity and reduced viability on in vitro cultures of OECs (Olfactory Ensheathing Cells) and SH-SY5Y cells.PM2.5 samples were collected in the metropolitan area of Catania, and the gravimetric determination of PM2.5, characterization of 10 trace elements and 16 polycyclic aromatic hydrocarbons (PAHs) were carried out for each sample. PM2.5 extracts were exposed to cultures of OECs and SH-SY5Y cells for 24-48-72 h, and the cell viability assay (MTT) was evaluated. Assessment of mitochondrial and cytoskeleton damage, and the assessment of apoptotic process were performed in the samples that showed lower cell viability.We have found an annual average value of PM2.5 = 16.9 μg/m3 and a maximum value of PM2.5 = 27.6 μg/m3 during the winter season. PM2.5 samples collected during the winter season also showed higher concentrations of PAHs and trace elements. The MTT assay showed a reduction in cell viability for both OECs (44%, 62%, 64%) and SH-SY5Y cells (16%, 17%, 28%) after 24-48-72 h of PM2.5 exposure. Furthermore, samples with lower cell viability showed a decrease in mitochondrial membrane potential, increased cytotoxicity, and also impaired cellular integrity and induction of the apoptotic process after increased expression of vimentin and caspase-3 activity, respectively.These events are involved in neurodegenerative processes and could be triggered not only by the concentration and time of exposure to PM2.5, but also by the presence of trace elements and PAHs on the PM2.5 substrate. The identification of more sensitive cell lines could be the key to understanding how exposure to PM2.5 can contribute to the onset of neurodegenerative processes.

Electron microscopy approach to the wetting dynamics of single organosilanized mesopores

Columnar mesoporous silicon (PSi) with hydrophobic vs. hydrophilic chemistries was chosen as a model for the local (pore-by-pore) study of water-pore interactions. Tomographic reconstructions provided a 3D view of the ramified pore structure. An in situ study of PSi wetting was conducted for categorized pore diameters by environmental scanning TEM. An appropriate setting of the contrast allows for the normalization of the gray scale in the images as a function of relative humidity (RH). This allows constructing an isotherm for each single pore and a subsequent averaging provides an isotherm for each pore size range. The isotherms systematically point to an initial adsorption through the formation of water adlayers, followed by a capillary filling process at higher RH. The local isotherms correlate with (global) gravimetric determination of wetting. Our results point at the validation of a technique for the study of aging and stability of single-pore nanoscale devices.

On the chemistry of small waterbodies linked to marine aerosols and local geology on the Windmill Islands and mainland near Casey Station, Antarctica

Context In total, 43 shallow waterbodies were sampled in 1983 in the vicinity of Casey Station and nearby islands in Antarctica. The following physico-chemical parameters were obtained: water and air temperature, pH, conductivity, dissolved oxygen, plus major and minor elements. Aims To identify the physico-chemical characteristics of these waters and determine their origin, and calculate their mineral saturation indices. Methods Waters were analysed using standard methods, including for some elements, flame-atomic absorption spectrometry, spectrophotometry, ion chromatography and gravimetric determination. Mineral saturation indices were calculated using the PHREEQ program. Key results Water salinities were generally low and in the range of 120–1200 mg L−1 (total dissolved solids, TDS), except for one site connected to the sea, and four slightly saline sites. The Na/Cl, Cl/Br and Ca/SO4 ratios of several waters were in the vicinity of seawater ratios, implying a contribution of marine aerosols. However, the Mg/Ca ratio of most waters departed from the seawater ratio, plus there was concordance between the molar ratios of (Na + K)/(Ca + Mg) of many of the waters sampled and those calculated from rock geochemical analyses from diverse lithologies. Such chemical ‘provincialism’ appears to be dictated by rock composition. Nitrate and phosphate concentrations were high in the vicinity of penguin rookeries. Conclusions Two sources of ions are identified, one as marine aerosols as shown by three sets of ratios (Na/Cl, Cl/Br and Ca/SO4) with known marine values, and the other from the weathering of local rocks as shown by (Na + K)/(Ca + Mg) of the lake waters compared to the same ratios for the surrounding rocks. Only a few waterbodies have saturation levels for several carbonate minerals (calcite, aragonite, dolomite and rhodochrosite). Implications Future work is recommended for monitoring the waterbodies surrounding Casey Station as a result of the increased atmospheric CO2 concentration that has occurred over the past 40 years, and likely also with the cessation of building activities around Casey Station.

We breathe pesticides: the presence of contaminants of the breathable and inhalable fractions of atmospheric particulate matter

Atmospheric air contamination by pesticides present in particulate matter is considered ubiquitous and can be found in different regions of the world. Atmospheric particulate matter can be collected by separating the fine from the coarse particles, simulating the action in the respiratory tract. The presence of pesticides in particulate matter fractionated by size was investigated in a peri-urban region, where agriculture is intense. Weekly samples were obtained using a cascade impactor. The gravimetric determination was obtained using an ultra-analytical balance. Identification and quantification of pesticides were obtained using UHPLC-MS/MS for 105 pesticides. The average concentration of total PM of 25.2 µg m-3 and maximum concentration of 44.2 µg m-3 were obtained. Azoxystrobin, carbendazim, chlorimuron, difenoconazole, diflubenzuron, ethephon, metolachlor, pyraclostrobin and trifloxystrobin were determined in the inhalable fraction (2.5 to 10.0 µm). In the fine fraction (1.0 to 2.5 µm) carbendazim, ethephon, metolachlor and trifloxystrobin were determined and in the 0.5 to 1.0 µm fraction, clomazone, ethoprophos, fenpropimorph, metalaxyl, pyrimethanil and propoxur were determined. Cyproconazole and metolachlor were determined in the <0.25 µm range and acephate was found in the coarse and fine ranges. The population in the region is exposed to possible risks when breathing particulate matter containing pesticides. These studies are essential to support public policies and more sustainable agricultural practices, promoting food security and environmental protection.

A New Acidity-Based Approach for Estimating Total Dissolved Solids in Acidic Mining Influenced Water

In natural waters, total dissolved solids (TDS) are usually estimated from electrical conductivity (EC) by applying a conversion factor (f). However, defining this conversion factor for mining influenced water is more complex since this type of water is highly mineralized and has complex chemical matrices. So, the present work aimed to establish a new conversion factor to estimate TDS from the classic parameters usually analyzed for the hydrochemical characterization of these contaminated waters. A total of 121 mining influenced water samples were collected in three mining areas representing pollution scenarios, such as acidic streams, acidic lagoons, and pit lakes. The parameters analyzed were pH, EC, sulfate, acidity, and TDS. The statistical analysis showed that TDS and acidity are related, with a high and significant correlation (r ≥ 0.964, ρ < 0.001), suggesting that this parameter could be an appropriate indicator to estimate the TDS. Moreover, although acidity analysis also involves laboratory work, the time and effort required are considerably less than the gravimetric determination of TDS. Hierarchical cluster analysis applied to these samples allowed the definition of seven classes, and their specific fmedian was calculated employing TDS/Acidity. Then, seven conversion factors were obtained for mining influenced water based on sulfate concentration and acidity degree.

Development and Validation of an Optimized Method for the Gravimetric Determination of volatile organic compounds in Silicone‐based Consumer Products

Development and Validation of an Optimized Method for the Gravimetric Determination of volatile organic compounds in Silicone‐based Consumer Products

ICP-OES-Analysis for Humic Substance

The possibilities of optical emission spectrometry with inductively coupled plasma (OES-ICP analysis) (in radial plasma observation) of humic preparations (HP) are evaluated, the proposed technique allows quantifying up to 24 elements (As, Al, B, Ba, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Mo, Na, Ni, P, Pb, Si, S, Sr, Ti, V and Zn). The list of these elements will allow determining the value of such preparations for soil nutrition, and will also help to avoid danger if the content of toxic impurities in them goes beyond their maximum permissible concentrations. In the absence of standard samples with certified contents of the elements to be determined, the correctness of the analysis for the macrocomponent composition is confirmed by comparing the results of gravimetric determination of the ash content of the studied objects with the calculated data obtained when processing the results of OES-ICP analysis. Systematic errors in the determination of trace impurities were minimized by using the method of adding standard solutions (from matrix influences), as well as 6 parallel measurements of samples prepared independently of each other. The correctness of the methodology was also evaluated by using model solutions close to the possible micro-impurity mineral composition of HP using the Student’s t-test. The results obtained for the isolated fraction of humic acids are compared with the literature data.

Chemical separation and measurement of platinum activation products

A method has been developed to purify and measure platinum radioisotopes in the presence of fission products and environmental constituents. The method uses a combination of cation exchange and anion exchange chromatography and selective precipitation steps to remove other radioisotopes from the sample. The addition of stable platinum carrier allows for a gravimetric determination of the chemical yield of the procedure. Overall, the method is fast, simple, and potentially applicable for rapid turnaround of unknown samples. Using this method, multiple platinum radioisotopes were measured in two different irradiation experiments. The measured ratios of the platinum radioisotopes clearly reflect the neutron spectrum of the irradiation, suggesting that platinum radioisotopes could be valuable signatures in nuclear forensic analyses.

Gravimetric geoid model determination of Central Ukraine area using combination of LSC and truncated SHA methods

Gravimetric geoid model determination of Central Ukraine area using combination of LSC and truncated SHA methods

Comparison of Recent Remote Sensing Data Using an Artificial Neural Network to Predict Soil Moisture by Focusing on Radiometric Indices

Remote sensing data is widely used as a common variable for digital soil mapping estimating models. The aim of this study, quite recently made available to researchers Operational Land Imager 2 (OLI–2) have structure Landsat 9 and Landsat 8 (OLI) and Sentinel 2A (MSI) to compare the performance of soil moisture estimation in multi-layer perceptron network (MLP) artificial intelligence algorithm of image data. The working area is 886.78 km2 and soil sampling was performed at 66 points for gravimetric soil moisture determination. In addition, after the satellite images were pre-processed, Soil Adjusted Vegetation Index (SAVI) and Normalized Difference Moisture Index (NDMI) were calculated. Landsat 9 (OLI-2) based SAVI and NDMI showed a moderately significant positive correlation relationship with gravimetric soil moisture (rSAVI-SM=0.62, rNMDI-SM=0.44). The relationship between Landsat 8 (OLI) (rSAVI-SM=0.57, rNDMI-SM=0.11) and Sentinel 2A (MSI) (rSAVI-SM=0.42, rNDMI-SM=0.27) based radiometric indices and soil moisture was lower than Landsat 9 (OLI-2). RMSE values of MLP models were found to be respectively 0.79, 1.16 and 1.17 for Landsat 9 (OLI-2), Landsat 8 (OLI) and Sentinel 2A (MSI). Our results showed that with an Operational Land Imager (OLI-2) and near and short-wave infrared wavelengths improvements to multispectral imaging have improved soil moisture estimation success.

DEVELOPMENT AND VALIDATION OF METHOD FOR ISOLATION AND QUANTITATIVE DETERMINATION OF WATER-SOLUBLE POLYSACCHARIDES FROM SUNFLOWER ROOTS OF ONE-YEAR-OLD

The aim of the study was to develop and validate an express method for the isolation and quantitative determination of water-soluble polysaccharides from the roots of sunflower of a one-year-old. To accelerate the process of extracting biologically active substances from the roots of one-year-old sunflower, as well as increasing the yield of water-soluble polysaccharides, it was decided to use an ultrasonic bath. Varying the process parameters, it was possible to select the optimal conditions for extracting water-soluble polysaccharides of sunflower roots of one-year-old under ultrasound treatment conditions: crushing of raw materials 0.5–1.0 mm, temperature – 80 °C, extraction rate – 3, duration of extractions - 30 minutes, ultrasound frequency – 30 kHz, ratio of raw materials and extractant 1 g per 15 ml. The proposed technique allows intensifying the process of producing water-soluble polysaccharides from sunflower roots of one-year old and reducing the time spent on it to 5–6 hours, as well as increasing the product yield to 16.29% in terms of absolutely dry raw materials. The developed technique is precision in the conditions of repeatability, correct, stable and has a fairly rigid linear dependence of the mass of the sediment on the mass of the analyzed raw materials in gravimetric determination of water-soluble polysaccharides in the roots of sunflower of a one-year-old. The procedure can be used for express analysis of the quality of sunflower roots of one-year old, as well as in industrial production of water-soluble polysaccharides from this kind of raw material.

Experimental investigation into paper dust formation during knife edge cutting on a laboratory scale

Abstract Especially in the field of paper and print post-processing on an industrial scale, continuous cutting operations generate paper dust. Despite preventive measures like dedusting units, a high paper web velocity induces the release of particulate dust. As a result, the particles settle and accumulate on machine components and in the surrounding area. Resuspended particles around a potential ignition source represent a fire hazard. The prevention of such fire incidents requires frequent servicing and maintenance. However, the shutdown time on industrial scale applications remains cost-intensive. In this research, a cutting plotter executes reproducible knife edge cutting sequences to identify significant parameters affecting the paper dust formation on a macro and micro scale. For this purpose, an extraction system collects the exposed particles along the cutting line. The applied methods include gravimetric determination of the dust mass and dynamic image analysis to characterise particle size and shape. Final results indicate a significant influence of the blade wear condition.

Multi-Glycomic Characterization of Fiber from AOAC Methods Defines the Carbohydrate Structures.

Dietary fiber has long been known to be an essential component of a healthy diet, and recent investigations into the gut microbiome-health paradigm have identified fiber as a prime determinant in this interaction. Further, fiber is now known to impact the gut microbiome in a structure-specific manner, conferring differential bioactivities to these specific structures. However, current analytical methods for food carbohydrate analysis do not capture this important structural information. To address this need, we utilized rapid-throughput LC-MS methods to develop a novel analytical pipeline to determine the structural composition of soluble and insoluble fiber fractions from two AOAC methods (991.43 and 2017.16) at the total monosaccharide, glycosidic linkage, and free saccharide level. Two foods were chosen for this proof-of-concept study: oats and potato starch. For oats, both AOAC methods gave similar results. Insoluble fiber was found to be comprised of linkages corresponding to β-glucan, arabinoxylan, xyloglucan, and mannan, while soluble fiber was found to be mostly β-glucan, with small amounts of arabinogalactan. For raw potato starch, each AOAC method gave markedly different results in the soluble fiber fractions. These observed differences are attributable to the resistant starch content of potato starch and the different starch digestion conditions used in each method. Together, these tools are a means to obtain the complex structures present within dietary fiber while retaining "classical" determinations such as soluble and insoluble fiber. These efforts will provide an analytical framework to connect gravimetric fiber determinations with their constituent structures to better inform gut microbiome and clinical nutrition studies.

Precise Purity Analysis of High-Purity Lanthanum Oxide by Gravimetric Analysis Assisted With Trace Elemental Analysis by Inductively Coupled Plasma Mass Spectrometry.

Gravimetric analysis was used to determine the purity of high-purity La2O3 by stepwise conversions of the weighing forms. In this study, lanthanum in the sample was converted to La oxalate, La2O3, and La2(SO4)3 to evaluate the stoichiometry of the weighing forms for accurate gravimetric determination. The losses of La in the filtrate, the washing solution of the precipitate, and the mechanical loss of La during filtration were measured using inductively coupled plasma optical emission spectrometry. The weighing forms were evaluated by comparing the observed mass ratio with the theoretical value at each conversion step. The final converted La2(SO4)3 was consistent with the theoretical composition based on the observed mass ratio of La2(SO4)3/La2O3. Additionally, impurities in the high-purity La2O3 were determined by inductively coupled plasma tandem mass spectrometry. The purity of the original La2O3 sample was precisely determined to be 99.977 % ± 0.057% (mass fraction as La2O3; the value following “±” indicates the expanded uncertainty with a coverage factor k = 2.18) by a combination of the gravimetric analysis using the precipitation from the homogeneous solution method and verification of the weighing forms for La compound.

A precise nanoparticle quantification approach using microfluidics and single-particle tracking

Due to the limited available amounts of components, especially of low water-soluble drugs, formulation development is often impeded by a careful characterization. The use of small batch sizes might solve this problem but requires also adequate analytics. Concentration of nanoparticulate formulations lack straightforward evaluation techniques. In this work, a precise and straight-forward method is established to individually count nanoparticles. A microfluidic chip with known dimensions was used to visualize single particles flowing through the channel (single-particle tracking (SPT)). A sequence of 10,000 images was analyzed to determine the mean particle concentration. The proposed method is independent of the particular flow rate through the microfluidic chip as long as there is no particle overlap and a continuous exchange of particles. Monodisperse Rhodamine B labeled poly (methyl methacrylate) (PMMA) nanoparticles (267.03 ± 9.79 nm) were used as a model and reference particle system for the evaluation process of SPT allowing for a gravimetric determination based on density analysis using analytical ultracentrifugation (AUC) and gas pycnometry. The SPT method was evaluated and compared to other techniques used for concentration measurement. Both approaches (SPT and gravimetry) provide very similar and comparable results indicating the applicability of this novel quantification approach. In contrast, multi angle dynamic light scattering (MADLS) could not yield a precision as good as SPT (number density rel. standard deviation SD nSPT = 11.67%; SD nMADLS = 49.45%). Finally, the measured particle number concentrations can be realized in low concentration ranges (0.8249 μg mL−1 – 0.08249 μg mL−1) not accessible for MADLS (0.08249 mg mL−1 – 0.008249 mg mL−1) and gravimetric analysis.

On the crystal-chemistry of meyerhofferite, CaB3O3(OH)5·H2O

The crystal structure and crystal chemistry of meyerhofferite, ideally CaB3O3(OH)5·H2O, was investigated by a multi-methodological approach based on titrimetric determination of boron, gravimetric determination of calcium, determination of fluorine by ion selective electrode, determination of water content by heating, other minor elements by inductively coupled plasma atomic emission spectroscopy, along with single-crystal synchrotron X-ray and neutron diffraction. The concentration of more than 50 chemical elements was measured. The combination of these techniques proves that the composition of meyerhofferite approaches the ideal one (i.e., (Ca1.012Mg0.003) (B2.984Si0.001)O3(OH)5·1.018H2O), with only a modest fraction of Mg (with MgO ≈ 0.03 wt%) replacing Ca, and with Si the only potential substituent of tetrahedral B (with SiO2 ≈ 0.02 wt%). The content of REE and other minor elements is, overall, not significant, including that of fluorine as a potential OH− substituent (i.e., < 0.01 wt%). These findings have some relevant geochemical and technical implications, here discussed. The X-ray and neutron structure model obtained in this study prove that the building units of the structure of meyerhofferite consist of: two BO2(OH)2 tetrahedra and one BO2(OH) triangle, linked by corner-sharing to form [B3O3(OH)5]2− rings, and distorted Ca-polyhedra (with CN = 8, CaO3(OH)4(OH2)), linked by edge-sharing to form infinite chains along [001]. The B3O3(OH)5 rings are connected to the Ca-polyhedra chains by corner- and edge-sharing, on two sides of the chains. These heteropolyhedral chains, made by Ca-polyhedra and B3O3(OH)5 rings, are mutually connected through hydrogen bonding only, giving rise to the tri-dimensional edifice of meyerhofferite. The neutron structure refinement showed no evidence of static or dynamic disorder pertaining to the H sites; their libration regime was found to be significantly anisotropic. At least seven of the nine oxygen sites of the structure are involved in H-bonding, as donors or as acceptors. The role played by the H-bonding scheme on the physical properties of meyerhofferite is discussed.