20346-99-0Relevant articles and documents
Facile Synthesis of Unsolvated Alkali Metal Octahydrotriborate Salts MB3H8 (M=K, Rb, and Cs), Mechanisms of Formation, and the Crystal Structure of KB3H8
Chen, Xi-Meng,Ma, Nana,Liu, Xin-Ran,Wei, Changgeng,Cui, Chong-Chao,Cao, Bu-La,Guo, Yanhui,Wang, Lai-Sheng,Gu, Qinfen,Chen, Xuenian
, p. 2720 - 2724 (2019)
A facile synthesis of heavy alkali metal octahydrotriborates (MB3H8; M=K, Rb, and Cs) has been developed. It is simply based on reactions of the pure alkali metals with THF?BH3, does not require the use of electron carriers or the addition of other reaction media such as mercury, silica gel, or inert salts as for previous procedures, and delivers the desired products at room temperature in very high yields. However, no reactions were observed when pure Li or Na was used. The reaction mechanisms for the heavy alkali metals were investigated both experimentally and computationally. The low sublimation energies of K, Rb, and Cs were found to be key for initiation of the reactions. The syntheses can be carried out at room temperature because all of the elementary reaction steps have low energy barriers, whereas reactions of LiBH4/NaBH4 with THF?BH3 have to be carried out under reflux. The high stability and solubility of KB3H8 were examined, and a crystal structure thereof was obtained for the first time.
One Ion, Many Facets: Efficient, Structurally and Thermally Sensitive Luminescence of Eu2+ in Binary and Ternary Strontium Borohydride Chlorides
Wylezich, Thomas,Sontakke, Atul D.,Castaing, Victor,Suta, Markus,Viana, Bruno,Meijerink, Andries,Kunkel, Nathalie
, (2019)
The Eu2+-doped mixed alkaline metal strontium borohydride chlorides ASr(BH4)3-xClx (A = K, Rb, Cs) and Eu2+-doped strontium borohydride chloride Sr(BH4)2-xClx have been prepared by mechanochemical synthesis. Intense blue photoluminescence for Sr(BH4)2-xClx (λem= 457 nm) and cyan photoluminescence for the perovskite-type mixed alkaline metal strontium borohydride chlorides ASr(BH4)3-xClx (A = K, Rb, Cs) (λem = 490 nm) is already observable after short milling times. Temperature dependent luminescence measurements reveal an appreciable blue shift with increasing temperature for all ASr(BH4)3-xClx (A = K, Rb, Cs) until 500 K. This extremely large shift, caused by structural relaxation, as well as the vibrationally induced emission band broadening can serve as a sensitive response signal for temperature sensing, and this unique behavior has, to the best of our knowledge, not been reported in any Eu2+ doped phosphor so far. Additionally, bright luminescence, high quantum efficiencies, and very low thermal quenching of these Eu2+-doped borohydrides show that such host materials could serve in solid state lighting applications.
Cation size and anion anisotropy in structural chemistry of metal borohydrides. the peculiar pressure evolution of RbBH4
Filinchuk, Yaroslav,Talyzin, Alexandr V.,Hagemann, Hans,Dmitriev, Vladimir,Chernyshov, Dmitry,Sundqvist, Bertil
, p. 5285 - 5292 (2010)
The pressure evolution of RbBH4 has been characterized by synchrotron powder X-ray diffraction and Raman spectroscopy up to 23 GPa. Diffraction experiments at ambient temperature reveal three phase transitions, at 3.0, 10.4, and 18 GPa (at 2.6,
Two new derivatives of scandium borohydride, MSc(BH4)4, M = Rb, Cs, prepared: Via a one-pot solvent-mediated method
Starobrat, Agnieszka,Jaroń, Tomasz,Grochala, Wojciech
, p. 11829 - 11837 (2019/08/13)
Two new derivatives of scandium borohydride, MSc(BH4)4, M = Rb, Cs, were prepared via two different synthetic methodologies-mechanochemical and solvent-mediated. The latter led to products free from the commonly present halide contamination, as evidenced by powder X-ray diffraction, FTIR spectroscopy and TGA/DSC/MS. The rubidium derivative crystallizes in an orthorhombic unit cell of the Pbcm space group in the structure which can be derived from ht-CrVO4, while CsSc(BH4)4 adopts a monoclinic (P21/c) unit cell which has monazite (CePO4) as a structural aristotype. Thermal decomposition of the samples obtained using the two methods was compared, evidencing the influence of lithium chloride on the decomposition reactions as well as chemical identity of the decomposition products. Uncontaminated MSc(BH4)4 salts decompose thermally yielding nearly pure hydrogen with the maximum decomposition rate at 230 °C and 235 °C, for M = Rb and Cs, respectively. Among the by-products of the solvent-mediated synthesis, a new cubic crystalline phase of M3ScCl6, M = Rb, Cs, has been detected.
Low-temperature Specific Heat of Rubidium Borohydride RbBH4
Gorbunov, V.E.,Gavrichev, K.S.,Bakum, S.I.
, p. 1754 - 1756 (2007/10/02)
The specific heat of RbBH4 has been studied in an adiabatic calorimeter.Two anomalies were detected on the Cp-T curve in the 25-52 K and 150-350 K ranges respectively.The thermodynamic properties of RbBH4 under standard conditions are: Cp0(198.15 K)=100.3+/-0.2 J K-1, S0(298.15 K)=126.6 +/-0.2 J K-1 mole-1, H0(298.15 K)-H0(0)=18210+/-40 J mole-1, -0(198.15 K)-H0(0)/298.15=65.54 J K-1 mole-1.
