Charge density in anhydrite, CaSO<sub>4</sub>. II. Static deformation density distributions from a multipole refinement

Kirfel, Α.; Will, Geoffrey

doi:10.1107/s056774088100352x

Cited by 10 publications

(6 citation statements)

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“…In the beginning the examination of the static deformation densities was the main basis of bonding type evaluations. [1,[35][36][37][38] Their results provided the first confirmation that bonding features were indeed accessible by accurate X-ray diffraction methods. However, it has been shown that the static deformation density cannot serve as the only means of analysis [39] because it is biased from the model-dependence of the promolecule describing the spherical ED, and the inappropriateness of the employed spherically averaged reference density.…”

Section: The Quantum Theory Of Atoms-in-moleculessupporting

confidence: 68%

Meaningful Structural Descriptors from Charge Density

Stalke

2011

Chemistry A European J

148

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This paper provides a short introduction to the basics of electron density investigations. The two predominant approaches for the modelling and various interpretations of electron density distributions are presented. Their potential translations into chemical concepts are explained. The focus of the article lies on the deduction of chemical properties from charge density studies in some selected main group compounds. The relationship between the obtained numerical data and commonly accepted simple chemical concepts unfortunately is not always straightforward, and often the chemist relies on heuristic connections rather than rigorously defined ones. This article tries to demonstrate how charge density analyses can shed light on aspects of chemical bonding and reactivity resulting from the determined bonding situation. Sometimes this helps to identify misconceptions and sets the scene for new unconventional synthetic approaches.

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Section: The Quantum Theory Of Atoms-in-moleculessupporting

confidence: 68%

Meaningful Structural Descriptors from Charge Density

Stalke

2011

Chemistry A European J

148

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“…Those analyses reveal the presence of three of the four well-known phenomena that occur when gypsum is heated (equations (1) to (4)). 8,9,[46][47][48] First, an endothermic dehydration in two steps occurs between 80°C and 200°C (equations (1) and (2)). Then, anhydrite III to anhydrite II exothermic phase transition is observed between 350°C and 400°C (equation 3).…”

Section: Materials Characterisationmentioning

confidence: 99%

“…Beyond this general context, the study of the gypsum hydration (from liquid to solid state) is largely represented in the literature, 5 –14 and so far, many references present the mechanical properties related to the microstructure of the final products. 4,12,15 –20 In the case of cast product, the average porosity (ε) is well controlled by the w/p.…”

Section: Introductionmentioning

confidence: 99%

Kinetics of internal structure evolution in gypsum board exposed to standard fire

Rojo

Mélinge

Guillou

2013

Journal of Fire Sciences

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International audienceGypsum is often used as passive fire protection. Indeed, its latent heat effect reduces heat transfer through the structure. To improve composition and physical properties of such material, it is necessary to model its behaviour. Heat and mass transfer have to be considered in the model. For a better understanding of phenomena occurring during a fire event, it is important to study the porosity. In this study, a porosity measurement protocol is developed. The porosity distribution along the thickness of large board sample subjected to standard fire (ISO 834) on one face is studied. In addition, scale effect is taken into account. Finally, the effect of temperature and microstructure are analysed

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“…In the beginning the examination of the static deformation densities was the main basis of bonding type evaluations 1. 35–38 Their results provided the first confirmation that bonding features were indeed accessible by accurate X‐ray diffraction methods. However, it has been shown that the static deformation density cannot serve as the only means of analysis39 because it is biased from the model‐dependence of the promolecule describing the spherical ED, and the inappropriateness of the employed spherically averaged reference density 40.…”

Section: The Quantum Theory Of Atoms‐in‐moleculesmentioning

confidence: 98%

Iron(III)‐Catalyzed Cyclization of Alkynyl Aldehyde Acetals: Experimental and Computational Studies

Yang

et al. 2010

Chemistry A European J

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DNA and RNA analysis is of high importance for clinical diagnoses, forensic analysis, and basic studies in the biological and biomedical fields. In this paper, we report the ultrahighly sensitive homogeneous detection of DNA and microRNA by using a novel single-silver-nanoparticle counting (SSNPC) technique. The principle of SSNPC is based on the photon-burst counting of single silver nanoparticles (Ag NPs) in a highly focused laser beam (about 0.5 fL detection volume) due to Brownian motion and the strong resonance Rayleigh scattering of single Ag NPs. We first investigated the performance of the SSNPC system and then developed an ultrasensitive homogeneous detection method for DNA and microRNA based on this single-nanoparticle technique. Sandwich nucleic acid hybridization models were utilized in the assays. In the hybridization process, when two Ag-NP-oligonucleotide conjugates were mixed in a sample containing DNA (or microRNA) targets, the binding of the targets caused the Ag NPs to form dimers (or oligomers), which led to a reduction in the photon-burst counts. The SSNPC method was used to measure the change in the photon-burst counts. The relationship between the change of the photon-burst counts and the target concentration showed a good linearity. This method was used for the assay of sequence-specific DNA fragments and microRNAs. The detection limits were at about the 1 fM level, which is 2-5 orders of magnitude more sensitive than current homogeneous methods.

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Charge density in anhydrite, CaSO₄. II. Static deformation density distributions from a multipole refinement

Cited by 10 publications

References 1 publication

Meaningful Structural Descriptors from Charge Density

Meaningful Structural Descriptors from Charge Density

Kinetics of internal structure evolution in gypsum board exposed to standard fire

Iron(III)‐Catalyzed Cyclization of Alkynyl Aldehyde Acetals: Experimental and Computational Studies

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Charge density in anhydrite, CaSO4. II. Static deformation density distributions from a multipole refinement

Cited by 10 publications

References 1 publication

Meaningful Structural Descriptors from Charge Density

Meaningful Structural Descriptors from Charge Density

Kinetics of internal structure evolution in gypsum board exposed to standard fire

Iron(III)‐Catalyzed Cyclization of Alkynyl Aldehyde Acetals: Experimental and Computational Studies

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Charge density in anhydrite, CaSO₄. II. Static deformation density distributions from a multipole refinement