Caesium hydrogen sulfate

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Caesium hydrogen sulfate
EntryWithCollCode85502.png
Identifiers
3D model (JSmol)
PubChem CID
Properties
CsHO4S
Molar mass 229.97 g·mol−1
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Caesium hydrogen sulfate or cesium hydrogen sulfate is the inorganic compound with formula CsHSO4. This colorless solid is the caesium salt of bisulfate. It is obtained by combining Cs2SO4 and H2SO4 [1]

An inorganic compound is typically a chemical compound that lacks C-H bonds, that is, a compound that is not an organic compound, but the distinction is not defined or even of particular interest.

Salt (chemistry) Ionic compound consisting of cations and anions

In chemistry, a salt is a solid chemical compound consisting of an ionic assembly of cations and anions. Salts are composed of related numbers of cations and anions so that the product is electrically neutral. These component ions can be inorganic, such as chloride (Cl−), or organic, such as acetate ; and can be monatomic, such as fluoride (F−), or polyatomic, such as sulfate.

Caesium sulfate chemical compound

Caesium sulfate or cesium sulfate is the inorganic compound and salt with the formula Cs2SO4. It is a white water-soluble solid that is used to prepare dense aqueous solutions for use in isopycnic (or "density-gradient") centrifugation. It is isostructural with potassium salt.

Contents

Properties

Above 141 °C, CsHSO4 is a superionic conductor. [1] The rapid ionic conductivity arise especially in the range of these temperatures due to the high activity of protons. [2]

In materials science, fast ion conductors are solids with highly mobile ions. These materials are important in the area of solid-state ionics, and are also known as solid electrolytes and superionic conductors. These materials are useful in batteries and various sensors. Fast ion conductors are used primarily in solid oxide fuel cells. As solid electrolytes they allow the movement of ions without the need for a liquid or soft membrane separating the electrodes. The phenomenon relies on the hopping of ions through an otherwise rigid crystal structure.

Proton nucleon (constituent of the nucleus of the atom) that has positive electric charge; symbol p

A proton is a subatomic particle, symbol
p
 or
p+
, with a positive electric charge of +1e elementary charge and a mass slightly less than that of a neutron. Protons and neutrons, each with masses of approximately one atomic mass unit, are collectively referred to as "nucleons".

Based on the results of X-ray crystallography, the structure consists of tetrahedral sulfate centers that bridge caesium ions. The proton is associated with the oxygen on sulfate. [3]

X-ray crystallography Technique used in studying crystal structure

X-ray crystallography (XRC) is the experimental science determining the atomic and molecular structure of a crystal, in which the crystalline structure causes a beam of incident X-rays to diffract into many specific directions. By measuring the angles and intensities of these diffracted beams, a crystallographer can produce a three-dimensional picture of the density of electrons within the crystal. From this electron density, the mean positions of the atoms in the crystal can be determined, as well as their chemical bonds, their crystallographic disorder, and various other information.

CsHSO4 goes through three crystalline phases that are referred to as phase III, II, and I. [4] CsHSO4 is initially existing in phase III at a room temperature of 21 °C. Phase III ranges from 21 °C to 90 °C with a transition temperature of 90 °C to 100 °C between phase III and phase II. Phase II ranges from 90 °C to 140 °C. At 140 °C, CsHSO4 undergoes a phase shift from phase II to phase I. [5]

Phase (matter) Region of space (a thermodynamic system), throughout which all physical properties of a material are essentially uniform; region of material that is chemically uniform, physically distinct, (often) mechanically separable

In the physical sciences, a phase is a region of space, throughout which all physical properties of a material are essentially uniform. Examples of physical properties include density, index of refraction, magnetization and chemical composition. A simple description is that a phase is a region of material that is chemically uniform, physically distinct, and (often) mechanically separable. In a system consisting of ice and water in a glass jar, the ice cubes are one phase, the water is a second phase, and the humid air is a third phase over the ice and water. The glass of the jar is another separate phase.

Phase III (21 °C to 90 °C) and Phase II (90 °C to 140 °C) are referred to as the monoclinic phases, in which CsHSO4 exhibits its lowest proton conductivity. As the crystalline structure’s temperature is raised, it will show variations in the unit cell volume and the arrangement of its hydrogen bonds, which will alter the ability of a CsHSO4 crystalline structure to allow the displacement of protons.

Monoclinic crystal system one of the 7 crystal systems in crystallography

In crystallography, the monoclinic crystal system is one of the 7 crystal systems. A crystal system is described by three vectors. In the monoclinic system, the crystal is described by vectors of unequal lengths, as in the orthorhombic system. They form a rectangular prism with a parallelogram as its base. Hence two vectors are perpendicular, while the third vector meets the other two at an angle other than 90°.

At 141 °C, the CsHSO4 crystal structure experiences a structural change from monoclinic phase II to a tetragonal phase, becoming phase I. Phase I has more elevated crystal symmetry and widened lattice dimensions. Phase I is noted as the superprotonic phase (strong conducting phase), which triggers an extreme growth in proton conductivity by four orders of magnitude, reaching 10 mS/cm. This makes the conductivity of CsHSO4 ten-fold stronger than the conductivity of a sodium chloride aqueous solution. In the superprotonic phase, the movement of an SO4 tetrahedron generates a disruption of the hydrogen bond network, which accelerates proton transfer. [5] The tetragonal anions available in the structure are accountable for the arrangement of the hydrogen bonds with the moving protons. [6]

Tetragonal crystal system lattice point group

In crystallography, the tetragonal crystal system is one of the 7 crystal systems. Tetragonal crystal lattices result from stretching a cubic lattice along one of its lattice vectors, so that the cube becomes a rectangular prism with a square base and height.

Sodium chloride Chemical compound

Sodium chloride, commonly known as salt, is an ionic compound with the chemical formula NaCl, representing a 1:1 ratio of sodium and chloride ions. With molar masses of 22.99 and 35.45 g/mol respectively, 100 g of NaCl contains 39.34 g Na and 60.66 g Cl. Sodium chloride is the salt most responsible for the salinity of seawater and of the extracellular fluid of many multicellular organisms. In its edible form of table salt, it is commonly used as a condiment and food preservative. Large quantities of sodium chloride are used in many industrial processes, and it is a major source of sodium and chlorine compounds used as feedstocks for further chemical syntheses. A second major application of sodium chloride is de-icing of roadways in sub-freezing weather.

Aqueous solution solution in which the solvent is water

An aqueous solution is a solution in which the solvent is water. It is mostly shown in chemical equations by appending (aq) to the relevant chemical formula. For example, a solution of table salt, or sodium chloride (NaCl), in water would be represented as Na+(aq) + Cl−(aq). The word aqueous (comes from aqua) means pertaining to, related to, similar to, or dissolved in, water. As water is an excellent solvent and is also naturally abundant, it is a ubiquitous solvent in chemistry. Aqueous solution is water with a pH of 7.0 where the hydrogen ions (H+) and hydroxide ions (OH−) are in Arrhenius balance (10−7).

Potential applications

The maximum conductivity of pure CsHSO4 is 10 mS/cm, which is too low for practical applications. In composites with SiO2, TiO2, and Al2O3) , the proton conductivity below the phase transition temperature is enhanced by a few orders of magnitude. [7]

Unlike hydrated protonic conductors, the absence of water in CsHSO4 provides thermal and electrochemical stability. Electromotive force (EMF) measurements in a humidified oxygen concentration cell verified the high ionic nature of CsHSO4 in its superprotonic phase. [8] Based on heat rotation, the voltage stayed the same for over 85 hours during the measurement, particularly at the high temperature. [8] These results, demonstrate the thermal independence from humidity-type environments. Additionally, the crystal structure of CsHSO4 allows for quick transport of smaller charged ions, resulting in efficient energy transfer in electrochemical devices.

Related Research Articles

Ionic compound chemical compound involving ionic bonding

In chemistry, an ionic compound is a chemical compound composed of ions held together by electrostatic forces termed ionic bonding. The compound is neutral overall, but consists of positively charged ions called cations and negatively charged ions called anions. These can be simple ions such as the sodium (Na+) and chloride (Cl−) in sodium chloride, or polyatomic species such as the ammonium (NH+
4) and carbonate (CO2−
3) ions in ammonium carbonate. Individual ions within an ionic compound usually have multiple nearest neighbours, so are not considered to be part of molecules, but instead part of a continuous three-dimensional network, usually in a crystalline structure.

Nafion chemical compound

Nafion is a brand name for a sulfonated tetrafluoroethylene based fluoropolymer-copolymer discovered in the late 1960s by Walther Grot of DuPont. Nafion is a brand of the Chemours company. It is the first of a class of synthetic polymers with ionic properties that are called ionomers. Nafion's unique ionic properties are a result of incorporating perfluorovinyl ether groups terminated with sulfonate groups onto a tetrafluoroethylene (PTFE) backbone. Nafion has received a considerable amount of attention as a proton conductor for proton exchange membrane (PEM) fuel cells because of its excellent thermal and mechanical stability.

Solid oxide fuel cell fuel cell that has a ceramic electrolyte

A solid oxide fuel cell is an electrochemical conversion device that produces electricity directly from oxidizing a fuel. Fuel cells are characterized by their electrolyte material; the SOFC has a solid oxide or ceramic electrolyte.

Water of crystallization

In chemistry, water of crystallization or water of hydration are water molecules that are present inside crystals. Water is often incorporated in the formation of crystals from aqueous solutions. In some contexts, water of crystallization is the total mass of water in a substance at a given temperature and is mostly present in a definite (stoichiometric) ratio. Classically, "water of crystallization" refers to water that is found in the crystalline framework of a metal complex or a salt, which is not directly bonded to the metal cation.

A proton conductor is an electrolyte, typically a solid electrolyte, in which H+ are the primary charge carriers.

A proton-exchange membrane, or polymer-electrolyte membrane (PEM), is a semipermeable membrane generally made from ionomers and designed to conduct protons while acting as an electronic insulator and reactant barrier, e.g. to oxygen and hydrogen gas. This is their essential function when incorporated into a membrane electrode assembly (MEA) of a proton-exchange membrane fuel cell or of a proton-exchange membrane electrolyser: separation of reactants and transport of protons while blocking a direct electronic pathway through the membrane.

Thallium(I) chloride chemical compound

Thallium(I) chloride, also known as thallous chloride, is a chemical compound with the formula TlCl. This colourless solid is an intermediate in the isolation of thallium from its ores. Typically, an acidic solution of thallium(I) sulfate is treated with hydrochloric acid to precipitate insoluble thallium(I) chloride. This solid crystallizes in the caesium chloride motif.

Thallium(I) iodide chemical compound

Thallium(I) iodide is a chemical compound with the formula TlI. It is unusual in being one of the few water-insoluble metal iodides, along with AgI, CuI, SnI2, SnI4, PbI2 and HgI2.

Caesium bromide chemical compound

Caesium bromide or cesium bromide is an ionic compound of caesium and bromine with the chemical formula CsBr. It is a white or transparent solid with a melting point a 636 °C that readily dissolves in water. Its bulk crystals have the cubic CsCl structure, but the structure changes to the rocksalt type in nanometer-thin film grown on mica, LiF, KBr or NaCl substrates.

Ice III tetragonal form of ice

Ice III is a form of solid matter which consists of tetragonal crystalline ice, formed by cooling water down to 250 K at 300 MPa. It is the least dense of the high-pressure water phases, with a density of 1160 kg/m3. The proton-ordered form of ice III is Ice IX.

Ionic conductivity is a measure of a substance's tendency towards ionic conduction. This involves the movement of an ion from one site to another through defects in the crystal lattice of a solid or aqueous solution.

An advanced superionic conductor (AdSIC) is fast ion conductor that has a crystal structure close to optimal for fast ion transport (FIT).

Rubidium silver iodide is a ternary inorganic compound with the formula RbAg4I5. Its conductivity involves the movement of silver ions within the crystal lattice. It was discovered while searching for chemicals which had the ionic conductivity properties of alpha-phase silver iodide at temperatures below 146 °C for AgI.

Genoa Joint Laboratories (GJL) is a scientific research activity founded in 2002, combining expertise in electroceramics and electrochemistry of three facilities: National Research Council - Institute for Energetics and Interphases (CNR-IENI), Department of Chemical and Process Engineering with University of Genova (DICHeP), and the Department of Chemistry and Industrial Chemistry with University of Genova (DCCI), all located in Genoa, Italy.

Solid state ionics

Solid-state ionics is the study of ionic-electronic mixed conductor and fully ionic conductors and their uses. Some materials that fall into this category include inorganic crystalline and polycrystalline solids, ceramics, glasses, polymers, and composites. Solid-state ionic devices, such as solid oxide fuel cells, can be much more reliable and long-lasting, especially under harsh conditions, than comparable devices with fluid electrolytes.

Sossina M. Haile is an Ethiopian-American chemist, known for developing the first solid acid fuel cells. She is a professor of Materials Science and Engineering at Northwestern University, Illinois, USA.

Rubidium hydrogen sulfate is the rubidium salt of sulfuric acid. It has the formula RbHSO4.

Solid acid fuel cells (SAFCs) are a class of fuel cells characterized by the use of a solid acid material as the electrolyte. Similar to proton exchange membrane fuel cells and solid oxide fuel cells, they extract electricity from the electrochemical conversion of hydrogen- and oxygen-containing gases, leaving only water as a byproduct. Current SAFC systems use hydrogen gas obtained from a range of different fuels, such as industrial-grade propane and diesel. They operate at mid-range temperatures, from 200 to 300 °C.

Sulfoxylic acid chemical compound

Sulfoxylic acid (H2SO2) (also known as hyposulfurous acid or sulfur dihydroxide) is an unstable oxoacid of sulfur in an intermediate oxidation state between hydrogen sulfide and dithionous acid. It consists of two hydroxy groups attached to a sulfur atom. Sulfoxylic acid contains sulfur in an oxidation state of +2. Sulfur monoxide (SO) can be considered as a theoretical anhydride for sulfoxylic acid, but it is not actually known to react with water.

References

  1. 1 2 Haile, Sossina M.; Boysen, Dane A.; Chisholm, Calum R. I.; Merle,Ryan B. (2001). "Solid acids as fuel cell electrolytes" (PDF). Nature. 410 (6831): 910–913. Bibcode:2001Natur.410..910H. doi:10.1038/35073536. PMID   11309611.CS1 maint: uses authors parameter (link)
  2. ↑ Sinitsyn, V. V. (2010). "Pressure effect on phase transitions in MeHAO4 superprotonic conductors (A = S, Se and Me = NH4, Rb, Cs)". Journal of Materials Chemistry. 20 (30): 6226–6234. doi:10.1039/c0jm00052c.
  3. ↑ Balagurov, A.M.; Beskrovnyi, A.I.; Savenko, B.N.; Merinov, B.V.; Dlouha, M.; Vratislav, S.; Jirak (1987). "The room temperature structure of deuterated CsHSO4 and CsHSeO4". Physica Status Solidi A. 100: 3–7. doi:10.1002/pssa.2211000146.
  4. ↑ Maja Mroczkowska-Szerszeń, Maciej Siekierski, Rafał Letmanowski, Michał Piszcz, Renata Cicha-Szot, Lidia Dudek, Sławomir Falkowicz, Grażyna Żukowska, and Magda Dudek. "Spectroscopic Verification of Extended Temperature Stability of Superionic Phase Obtained in Mechanosyntehsis Process for CsHSO4/Phospho-silicate Glass Composite." Oil and Gas Institute, Ul. Lubicz 25a, 31-503 Cracow, Poland/Warsaw University of Technology Faculty of Chemistry, Inorganic Chemistry and Solid State Technology Division Ul.Noakowskiego 3, 00-640 Warsaw, Poland 3AGH – University of Science and Technology, Faculty of Fuels and Energy, Al. Mickiewicza 30, 30-059 Cracow, Poland, n.d. Web.
  5. 1 2 Otomo, Junichiro; Shigeoka, Hitoshi; Nagamoto, Hidetoshi; Takahashi, Hiroshi (2005). "Phase transition behavior and proton conduction mechanism in cesium hydrogen sulfate/silica composite". Journal of Physics and Chemistry of Solids. 66 (1): 21–30. Bibcode:2005JPCS...66...21O. doi:10.1016/j.jpcs.2004.07.006.
  6. ↑ Chan, Wing Kee. Structure and dynamics of hydrogen in nanocomposite solid acids for fuel cell applications. TU Delft, Delft University of Technology, 2011.
  7. ↑ Hiroki Muroyama, Toshiaki Matsui, Ryuji Kikuchi, and Koichi Eguchi. "Composite Effect on the Structure and Proton Conductivity for CsHSO4 Electrolytes at Intermediate Temperatures." (n.d.): n. pag. Department of Energy and Hydrocarbon Chemistry, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8510, Japan, 13 Apr. 2006. Web.
  8. 1 2 Uda, Tetsuya, Dane A. Boysen, and Sossina M. Haile. "Thermodynamic, thermomechanical, and electrochemical evaluation of CsHSO 4." Solid State Ionics 176.1 (2005): 127-133.
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