Chemical Formulas and Nomenclature

2021 ◽  
pp. 31-42
Author(s):  
Christopher O. Oriakhi
Keyword(s):  
Chemical Formula ◽  
Oxidation Number ◽  
Molecular Compounds ◽  
Chemical Formulas

Chemical Formula and Nomenclature explains the rules for writing chemical formulas and naming compounds. The concept of oxidation number and how to determine it within a molecule or a polyatomic ion is described. Rules for writing and naming ionic and molecular compounds are discussed.

Molecular and electronic structure of AnIVFeII(CN)6·xH2O (An = Th, U, Np) compounds: an X-ray absorption spectroscopy investigation

2000 ◽  
Vol 78 (10) ◽  
pp. 1305-1317
Author(s):  
Isabelle Bonhoure ◽  
Christophe Den Auwer ◽  
Christophe Cartier dit Moulin ◽  
Philippe Moisy ◽  
Jean-Claude Berthet ◽  
...  
Keyword(s):  
Absorption Spectroscopy ◽  
Molecular Structures ◽  
Oxidation States ◽  
X Ray Diffraction ◽  
Acidic Media ◽  
X Ray ◽  
X Ray Absorption ◽  
Molecular Compounds ◽  
Molecular And Electronic Structure ◽  
Chemical Formulas

AnIVFeII(CN)6·xH2O (An = Th, U, Np) molecular compounds have been prepared by precipitation from acidic media. These microcrystalline compounds have been characterized by infrared spectroscopy, X-ray diffraction, and X-ray absorption spectroscopy. They have been found to be isostructural with the LnIIIKFeII(CN)6·4H2O compounds. The molecular structures of these compounds are presented and their chemical formulas are given: in all compounds, the Fe(CN)6 octahedra is conserved and the An ion is linked to the N atoms of the CN ligands. The formal oxidation states are also discussed.Key words: hexacyanoferrate, actinide, EXAFS, XANES, X-ray absorption spectroscopy.

scholarly journals Application of stoichiometric hydrogen atoms for balancing organic combustion reactions

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Pong Kau Yuen ◽  
Cheng Man Diana Lau
Keyword(s):  
Organic Chemical ◽  
Chemistry Curriculum ◽  
Hydrogen Atoms ◽  
Oxidation Number ◽  
Simple Arithmetic ◽  
General Chemical ◽  
Redox Indicator ◽  
Mathematical Formulas ◽  
The Relationship ◽  
Chemical Formulas

Abstract Combustion is a common redox reaction, and organic combustion is one of the basic contents in chemistry curriculum. The transferred H-atom is commonly used as a redox indicator in organic chemistry and biochemistry. Nevertheless, the relationship between the number of transferred H-atoms and the number of transferred electrons has not been fully revealed. Oxidation number (ON) is an electron-counting concept. Without knowing the ONs, the number of transferred electrons cannot be counted and therefore, the redox reactions cannot be classified, defined, and balanced. This paper explores the new H-atom method for counting the number of transferred H-atoms. It provides a half-reaction approach to balance the overall organic combustion reactions. Only simple arithmetic procedures are needed to determine the number of transferred H-atoms and consequently the number of transferred electrons. According to this method, the mathematical formulas for assigning the number of transferred H-atoms can be deducted by balancing the general chemical formulas of organic compounds in half and overall organic combustions. Furthermore, the number of transferred electrons and their stoichiometric categories can be determined conveniently by any given organic chemical formula in organic combustion reactions.

A neutron diffraction study of hydrogen bonding in the deuterium (hydrogen) L-arginine phosphate monohydrate

1997 ◽  
Vol 212 (3) ◽  
Author(s):  
Z. Cheng ◽  
Y. Cheng ◽  
L. Guo ◽  
D. Xu
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonding ◽  
Neutron Diffraction ◽  
Diffraction Study ◽  
Title Compound ◽  
Neutron Diffraction Study ◽  
Chemical Formula

AbstractThe crystal structure of the title compound D(H)LAP with chemical formula (D

A Transferable, Polarisable Force Field for Ionic Liquids

2019 ◽  
Author(s):  
Kateryna Goloviznina ◽  
José N. Canongia Lopes ◽  
Margarida Costa Gomes ◽  
Agilio Padua
Keyword(s):  
Ionic Liquids ◽  
Force Field ◽  
Force Fields ◽  
Dipole Moments ◽  
Van Der Waals Interactions ◽  
First Principles Calculations ◽  
Ion Diffusion ◽  
Fixed Integer ◽  
Molecular Compounds ◽  
Induced Dipoles

A general, transferable polarisable force field for molecular simulation of ionic liquids and their mixtures with molecular compounds is developed. This polarisable model is derived from the widely used CL\&P fixed-charge force field that describes most families of ionic liquids, in a form compatible with OPLS-AA, one of the major force fields for organic compounds. Models for ionic liquids with fixed, integer ionic charges lead to pathologically slow dynamics, a problem that is corrected when polarisation effects are included explicitly. In the model proposed here, Drude induced dipoles are used with parameters determined from atomic polarisabilities. The CL\&P force field is modified upon inclusion of the Drude dipoles, to avoid double-counting of polarisation effects. This modification is based on first-principles calculations of the dispersion and induction contributions to the van der Waals interactions, using symmetry-adapted perturbation theory (SAPT) for a set of dimers composed of positive, negative and neutral fragments representative of a wide variety of ionic liquids. The fragment approach provides transferability, allowing the representation of a multitude of cation and anion families, including different functional groups, without need to re-parametrise. Because SAPT calculations are expensive an alternative predictive scheme was devised, requiring only molecular properties with a clear physical meaning, namely dipole moments and atomic polarisabilities. The new polarisable force field, CL\&Pol, describes a broad set set of ionic liquids and their mixtures with molecular compounds, and is validated by comparisons with experimental data on density, ion diffusion coefficients and viscosity. The approaches proposed here can also be applied to the conversion of other fixed-charged force fields into polarisable versions.<br>

Characterization of Amethysts from Sukamara, Central Kalimantan, Using Laser-Induced Breakdown Spectroscopy (LIBS)

2020 ◽  
Vol 1 (2) ◽  
pp. 5-8
Author(s):  
Komang Gde Suastika, Heri Suyanto, Gunarjo, Sadiana, Darmaji
Keyword(s):  
Emission Intensity ◽  
Laser Energy ◽  
Emission Spectra ◽  
Atomic Emission ◽  
Laser Induced Breakdown Spectroscopy ◽  
Chemical Formula ◽  
Central Kalimantan ◽  
Breakdown Spectroscopy ◽  
Laser Induced Breakdown

Abstract - Laser-Induced Breakdown Spectroscopy (LIBS) is one method of atomic emission spectroscopy using laser ablation as an energy source. This method is used to characterize the type of amethysts that originally come from Sukamara, Central Kalimantan. The result of amethyst characterization can be used as a reference for claiming the natural wealth of the amethyst. The amethyst samples are directly taken from the amethyst mining field in the District Gem Amethyst and consist of four color variations: white, black, yellow, and purple. These samples were analyzed by LIBS, using laser energy of 120 mJ, delay time detection of 2 μs and accumulation of 3, with and without cleaning. The purpose of this study is to determine emission spectra characteristics, contained elements, and physical characteristics of each amethyst sample. The spectra show that the amethyst samples contain some elements such as Al, Ca, K, Fe, Gd, Ba, Si, Be, H, O, N, Cl and Pu with various emission intensities. The value of emission intensity corresponds to concentration of element in the sample. Hence, the characteristics of the amethysts are based on their concentration value. The element with the highest concentration in all samples is Si, which is related to the chemical formula of SiO2. The element with the lowest concentration in all samples is Ca that is found in black and yellow amethysts. The emission intensity of Fe element can distinguish between white, purple, and yellow amethyst. If Fe emission intensity is very low, it indicates yellow sample. Thus, we may conclude that LIBS is a method that can be used to characterize the amethyst samples.Key words: amethyst, impurity, laser-induced, breakdown spectroscopy, characteristic, gemstones

(+)-3-Carene: Valuable Starting Material for Synthesis of Low-molecular Compounds with Olfactory Properties

2014 ◽  
Vol 18 (4) ◽  
pp. 446-458 ◽  
Author(s):  
Daniel Strub ◽  
Lucyna Balcerzak ◽  
Stanislaw Lochynski
Keyword(s):  
Starting Material ◽  
Molecular Compounds

Adsorption and Oxidation of Thiosulfate on the Platinum Electrode in a Slightly Alkaline Medium

2000 ◽  
Vol 65 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Tomáš Loučka
Keyword(s):  
Alkaline Medium ◽  
Oxidation Reaction ◽  
Open Circuit Potential ◽  
Platinum Electrode ◽  
Adsorbed Layer ◽  
Open Circuit ◽  
Adsorbed Hydrogen ◽  
Oxidation Number ◽  
Hydrogen Electrode ◽  
Layer Region

The aim of this research was to study the oxidation and reduction of the adsorbed thiosulfate on the platinum electrode in a slightly alkaline medium. The adsorption was performed at the open circuit conditions. The reduction of the adsorbed layer in the hydrogen region is slower in a slightly alkaline medium than in acid. The mechanism of reduction and oxidation of adsorbed molecules is probably the same. The nonstationary currents measured in presence of thiosulfates showed that the change in the oxidation number does not take place during the adsorption in the double layer region. In the hydrogen region, thiosulfate replaces the adsorbed hydrogen while beeing reduced. Nonstationary currents at higher concentrations of thiosulfate indicate the presence of more layers on the electrode. Upon reaching higher concentrations of thiosulfate the oxidation reaction takes place between thiosulfate in solution and adsorbed product of its reduction. The open circuit potential of the platinum electrode measured in a thiosulfate solution was 0.780 and 0.783 V against the hydrogen electrode in the same solution.

Reactions

2011 ◽  
Author(s):  
Peter Atkins
Keyword(s):  
Chemical Reactions ◽  
Molecular Level ◽  
Chemical Processes ◽  
Chemical Formula ◽  
Complex Processes ◽  
Full Color ◽  
Chemistry Textbooks ◽  
Simple Chemical ◽  
The Subject ◽  
Solid Form

Illustrated with remarkable new full-color images--indeed, one or more on every page--and written by one of the world's leading authorities on the subject, Reactions offers a compact, pain-free tour of the inner workings of chemistry. Reactions begins with the chemical formula almost everyone knows--the formula for water, H2O--a molecule with an "almost laughably simple chemical composition." But Atkins shows that water is also rather miraculous--it is the only substance whose solid form is less dense than its liquid (hence ice floats in water)--and incredibly central to many chemical reactions, as it is an excellent solvent, being able to dissolve gases and many solids. Moreover, Atkins tells us that water is actually chemically aggressive, and can react with and destroy the compounds dissolved in it, and he shows us what happens at the molecular level when water turns to ice--and when it melts. Moving beyond water, Atkins slowly builds up a toolkit of basic chemical processes, including precipitation (perhaps the simplest of all chemical reactions), combustion, reduction, corrosion, electrolysis, and catalysis. He then shows how these fundamental tools can be brought together in more complex processes such as photosynthesis, radical polymerization, vision, enzyme control, and synthesis. Peter Atkins is the world-renowned author of numerous best-selling chemistry textbooks for students. In this crystal-clear, attractively illustrated, and insightful volume, he provides a fantastic introductory tour--in just a few hundred colorful and lively pages - for anyone with a passing or serious interest in chemistry.

Crystal structure of KBSi3O8 isostructural with danburite

1993 ◽  
Vol 57 (386) ◽  
pp. 157-164 ◽  
Author(s):  
Mitsuyoshi Kimata
Keyword(s):  
Crystal Structure ◽  
Direct Method ◽  
Crystal Chemical ◽  
Chemical Formula ◽  
Crystal Chemical Formula ◽  
3 Dimensional ◽  
Tetrahedral Sites ◽  
Structural Types ◽  
Coupled Substitution ◽  
Insight Into

AbstractThe crystal structure of KBSi3O8 (orthorhombic, Pnam, with a = 8.683(1), b = 9.253(1), c = 8.272(1) Å,, V = 664.4(1) Å3, Z = 4) has been determined by the direct method applied to 3- dimensional rcflection data. The structure of a microcrystal with the dimensions 20 × 29 × 37 μm was refined to an unweightcd residual of R = 0.031 using 386 non-zero structure amplitudes. KBSi3O8 adopts a structure essentially different from recdmergneritc NaBSi3O8, with the low albite (NaAlSi3O8) structure, and isotypic with danburite CaB2Si2Os which has the same topology as paracelsian BaAl2Si2O8. The chenfical relationship between this sample and danburitc gives insight into a new coupled substitution; K+ + Si4+ = Ca2+ + B3+ in the extraframework and tetrahedral sites. The present occupancy refinement revealed partial disordering of B and Si atoms which jointly reside in two kinds of general equivalent points, T(1) and T(2) sites. Thus the expanded crystal-chemical formula can be written in the form K(B0.44Si0.56)2(B0.06Si0.94)2O8The systematic trend among crystalline compounds with the M+T3+T4+3O8 formula suggests that they exist in one of four structural types; the feldspar structures with T3+/T4+ ordered and/or disordered forms, and the paracelsian and the hollandite structures.

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