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Singh Swati Bawitlung Laldingngheti Singh Munmun Kumar Chauhan Amit Padalia Rajendra Chandra Pal Anirban Verma Ram Swaroop 《Chemistry of Natural Compounds》2022,58(1):161-162
Chemistry of Natural Compounds - 相似文献
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Two new equiatomic ternary compounds, EuPtSi and EuPdSi, have been synthesized and are found to crystallize in the cubic LaIrSi type structure. The magnetic susceptibility of both compounds follows Curie-Weiss behavior in the temperature range 10 to 300 K with an effective magnetic moment close to that of Eu2+ moment. The paramagnetic Curie temperatures are 5 K for EuPtSi and 9 K for EuPdSi. There is no clear indication of magnetic ordering in the susceptibility of both the compounds down to 4.2 K. However, 151Eu Mössbauer studies show a hyperfine split pattern in EuPtSi at 4.2 K indicating the onset of magnetic ordering. The 151Eu isomer shifts are temperature independent and are characteristic of the divalent Eu ion. All these results establish that the Eu ions are in a stable divalent state in these compounds. 相似文献
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The leaf and inflorescence essential oils of Plectranthus rugosus Wall. (syn. Rabdosia rugosa Wall.) and Plectranthus incanus L. (syn. Plectranthus mollis L.), which grow wild in Uttarakhand, India, were analysed and compared by capillary gas chromatography and gas chromatography-mass spectrometry. The analysis led to the identification of 43 constituents, forming 89.5-93.6% of the total oil compositions. Both leaf and inflorescence oil of P. rugosus were dominated by sesquiterpene hydrocarbons (71.8%, 71.7%) represented by β-caryophyllene (36.2%, 29.8%), germacrene D (25.2%, 28.2%) and α-humulene (6.6%, 8.6%) as the major constituents. Conversely, the leaf and inflorescence oil of P. incanus were dominated by monoterpenoids (74.4%, 65.8%) with piperitenone oxide (44.2%, 38.5%), piperitone (8.6%, 12.2%) and terpinolene (14.5%, 10.2%) as major constituents. Piperitenone oxide, piperitone, cis- and trans-piperitols and trans-piperitol acetate were the marker constituents in P. incanus, which were not noted in the essential oil of P. rugosus. 相似文献
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Sujata Patil R. Nagarajan L. C. Gupta C. Godart R. Vijayaraghavan B. D. Padalia 《Hyperfine Interactions》1988,42(1-4):1063-1066
The series Eu2M3Si5 (M=Ni, Cu, Pd, Rh) have been synthesised for the first time. The Ni, Cu, Pd systems form in U2Co3Si5 type structure.151Eu Mössbauer spectroscopy shows that Eu is in valence fluctuating (VF) state in Ni system, while in Cu and Pd systems it is in stable divalent state. These observations are further confirmed by magnetic susceptibility studies. The material Eu2Rh3Si5 shows two lines in the Mössbauer resonance, one of which shows VF behaviour. 相似文献
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D. T. Adroja R. Nagarajan S. K. Malik B. D. Padalia R. Vijayaraghavan 《Hyperfine Interactions》1988,41(1):535-538
New ternary compounds having the formula EuTCu4 where T=Al, Pd and Ag have been synthesized. All these compounds are found to crystallize in the hexagonal CaCu5 type structure. Magnetization measurements reveal that these compounds are magnetically ordered with magnetic moments close to 7 μB. The Curie temperatures obtained from low field ac susceptibility measurements are 26K, 25K and 50K for T-Al, Pd and Ag respectively.151Eu Mössbauer studies at room temperature show a large negative isomer shift relative to SmF3. A hyperfine split pattern is observed at 4.2K in all these compounds, indicating that Eu ion is present in a divalent state and is magnetically ordered. 相似文献
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B.D. Padalia V. Prabhawalkar 《Journal of Electron Spectroscopy and Related Phenomena》1985,36(1):11-16
The 3d core-level X-ray photoelectron spectra of rare earths (R) in RMn2Si2 (R = Pr, Nd, Sm, Gd) and RGa2 (R = Pr, Nd, Sm) have been recorded. A structure has been detected on the low binding energy side of each of the 3d and 3d photoemission peaks. The structure identified as a shake-down satellite shows no chemical shift. The energy separation of the satellite has been measured with respect to the main 3d peak. The present results have been examined in the light of recent experimental and theoretical reports. 相似文献
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Essential oils derived from six different phenophases, namely early vegetative stage, late vegetative stage, early flowering stage, full flowering stage (FFS), late flowering stage and seed shattering stage of Origanum vulgare L. grown in Kumaon region of Uttarakhand, India were investigated by GC and GC-MS. A total of 38 constituents, representing 97.4-99.7% of the total oil composition, were identified. Major components of oils were thymol (40.9-63.4%), p-cymene, (5.1-25.9%), γ-terpinene (1.4-20.1%), bicyclogermacrene (0.2-6.1%), terpinen-4-ol (3.5-5.9%), α-pinene (1.6-3.1%), 1-octen-3-ol (1.4-2.7%), α-terpinene (1.0-2.2%), carvacrol (<0.1-2.1%), β-caryophyllene (0.5-2.0%) and β-myrcene (1.2-1.9%). Thymol, terpinen-4-ol, 3-octanol, α-pinene, β-pinene, 1,8-cineole, α-cubebene and (E)-β-ocimene were observed to be higher during FFS. The study showed that plant stage had a significant effect on the essential oil content and composition of O. vulgare grown in the hilly tracks of Northern India. 相似文献
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R. Nagarajan E.V. Sampathkumaran L.C. Gupta R. Vijayaraghavan B.D. Padalia 《Physics letters. A》1981,81(7):397-398
L3 X-ray absorption spectroscopic study of Eu firmly establishes that the compound, EuPd2Si2, is a mixed valence system. It is found that the relative intensities of the absorption peaks corresponding to divalent and trivalent europium ions in EuPd2Si2 are a strong function of temperature. 相似文献