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Users should refer to the original published version of the material for the full abstract.

No warranty is given about the accuracy of the copy. However, users may print, download, or email articles for individual use. Copyright of International Journal of Energy Research is the property of Hindawi Limited and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission.In terms of their physical properties, the elements of Group 1 are soft metals with low-melting points. From the optical properties, it is found that these materials possess high absorption and refractive index, due to which it can be deemed as a suitable candidate for optical lenses and optical coating materials. Caesium was their first major discovery using the spectroscope, followed quickly in 1861 by rubidium. Optical properties, such as real and imaginary parts of dielectric functions, reflectivity, extinction coefficients, absorption coefficients, optical conductivity, and refractive indices, are also calculated in the energy range 0 to 30 eV. For more clarification of electronic properties, the DOS presents the different contributions of valence states to valence and conduction bands. Band structures and density of states (DOS) are performed for the computation of electronic properties and it is found that the calculated bandgap of CsHgF3 is of an indirect and semiconductive nature, while CsHgCl3 reveals metallic nature.

It is observed from the elastic properties measurements that these compounds are ductile, anisotropic, and mechanically stable.

Elastic parameters, such as anisotropic factor, bulk modulus, elastic constants, Pugh's ratio, and Poisson's ratio, are predicted. The crystals are very hygroscopic and gradually disintegrate at ambient conditions. It readily dissolves in water with the maximum solubility increasing from 1865 g/L at 20 C to 2705 g/L at 100 C. It will react with water even at temperatures as low as 116 C. It is the least electronegative element and is extremely reactive and even pyrophoric. It has a very low melting point of 28 C, meaning it can be a liquid at near room temperature or if held in one's hand. The obtained optimized lattice parameters are found to agree with available experimental and other theoretical data. Caesium chloride is colorless in the form of large crystals and white when powdered. Physical Caesium is a soft alkali metal, silvery-gold in color.

Abstract: Summary: Structural, elastic, electronic, and optical properties of Cs‐based halide perovskite compounds CsHgX3 (X═F and Cl) are computed in the framework of density functional theory (DFT). ATOMIC MASS 132.9054 FAMILY Group 1 (IA) Alkali metal > PRONUNCIATION SEE-zee-um Cesium is not a common element, and it has few commercial uses.

The conductivity is also suppressed by application of pressure (about 10 times decrease at 0.4 GPa) which reduces the mobility of lattice vacancies. It then sharply drops by two orders of magnitude because of the phase transition from the α-CsCl to β-CsCl phase. The conductivity increases with temperature up to about 450 ☌, with an activation energy changing from 0.6 to 1.3 eV at about 260 ☌. It occurs through nearest-neighbor jumps of lattice vacancies, and the mobility is much higher for the Cl- than Cs+ vacancies. The conductivity has a value of the order 10−7 S/cm at 300 ☌. Caesium chloride has also a relatively high solubility in formic acid (1077 g/L at 18 ☌) and hydrazine medium solubility in methanol (31.7 g/L at 25 ☌) and low solubility in ethanol (7.6 g/L at 25 ☌), sulfur dioxide (2.95 g/L at 25 ☌), ammonia (3.8 g/L at 0 ☌), acetone (0.004% at 18 °С), acetonitrile (0.083 g/L at 18 °С), ethylacetates and other complex ethers, butanone, acetophenone, pyridine and chlorobenzene.ĭespite its wide band gap of about 8.35 eV at 80 K, caesium chloride weakly conducts electricity, and the conductivity is not electronic but ionic. In contrast to sodium chloride and potassium chloride, caesium chloride readily dissolves in concentrated hydrochloric acid. It readily dissolves in water with the maximum solubility increasing from 1865 g/L at 20 ☌ to 2705 g/L at 100 ☌. Caesium chloride is colorless in the form of large crystals and white when powdered.