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1.
原子核。同位素。电子云。电子层和电子亚层。s电子云和p电子云的图象。d电子,f电子。电子的自旋。 H到Kr的电子层排布。原子结构与周期系。元素周期表根据原子的电子层结构分区~*。化学键。离子键。共价键。配位键。元素的电负性。极性分子与非极性分子。氢键。离子晶体。原子晶体。分子晶体。  相似文献   

2.
信息与服务     
O协。N00。闪00。NO仍。门00。价00.州O叭。N00。N00。价00。曰00。仍00。NO叭。N00。NO叭。NON。1O叭。N00。NO口户N00。N00。N00 .2O叭。NO仍。阶O叭。N恤习l四1尺!浑号。补半甥冷坎卜O﹃邢日补牟欢咨比解琴劣卞穴答.’补妞小佘褪众吝︸补牟别滓穴名︸朴牟澎褥尺g︹补习书叹权一09旧哄习。谧补故补半哭长习汉任中成外曰州。066一闪一。一协6一Z一.一66一内一。1661州一。1661刊一.一66一10.16伍一刊︸。1661叫︻.0661州一。1661N一。︻661N工.1661N一。︻661N一。一66︻囚州。1661一0.州66一囚一。工比61一O。叫6小︻州0.问…  相似文献   

3.
高中二年级(每周4课时,共128课时)(一)物质结构(25)原子核。同位素。电子云。电子层和电子亚层。s电子云和p电子云的图象。d电子、f电子。电子的自旋。H到Kr的电子层结构。原子结构与周期系。元素周期表根据原子的电子层结构分区。化学键。离子键。共价键。键角和键能(与生成热相联系)。配位键。元素的电负性。极性  相似文献   

4.
复习初中学过的重要基础知识和基本技能。(9) (一)摩尔(12)物质的量的单位——摩尔。阿佛加德罗常数。关于摩尔的计算。气体的摩尔体积及其计算。溶液的摩尔浓度及其计算。反应热及其计算。热化学方程式。燃烧热。说明:中和热在高二讲述。  相似文献   

5.
以wag/P”-AI。O。为固体电解质的CO。、SO。、NO。等气体传感器的研究已有很多报道[‘-‘],多采用的是个AI。O。结构的电解质。AI刀。和p”-AI刃。的结构具有一定的相似性,但后者具有更高的迁移离子浓度和更开放的晶体结构,表现出更好的离子导电性‘’‘.由于卢”-AI。O。为介稳结构,需要加入如Li。O、MgO等作为稳定剂才能稳定存在.以Li对稳定的产”-al。O。烧结较容易,P”-AI。O。相转化率高,但以MsO为稳定剂制备的”-AI刃。其显微结构和抗吸湿性能更为优越.LJLi对和MgO共同稳定的产”-AI。O。可以…  相似文献   

6.
————3”区Li“川—产队 究所‘”然科学版)-仪阿4”y卜人于2。。。。。中。。。。。。。。。。17 吉霉坤”””’”。。。。。。。中。。。。。。。。。。r。。。。,。中。。。。旧。。。。。。。g”“““g票寞宗羌民’-4。。。华。、。。中。。。中华。。。19。。。。。;2腆-厂 北。机。。。。5 物理学报 中国科学院 中科院物理所20 上海环境科学 上海市 卜海市环保局6 高等学校化学学报 教育部)}林大学、南“大ZI 中国药学杂志 中国科协 中国医学会7 金属学报 中国科协 中国金属学会22 金种铸。及有色合 中国科快 中闷机械工程学《…  相似文献   

7.
第26届国际化学奥林匹克竞赛理论试题答案吴国庆编译(北京师范大学化学系100875)8一@(a)HL十H。O—H。O十十L-K。。一1.4·10-‘;C。。一3.00·回旷’K。。一[H。O”]’/{C。。一[H。O”」}(·;C/K—3·10-’/...  相似文献   

8.
新,传播新知建功勋。促四化,培育后来人。基,根深叶茂果如期。培沃土,百花满生机。通,杂交渗透贯纵横。百科间,万里架长虹。普,善把艰深化通俗。读者众,效益更突出。  相似文献   

9.
TiO2-Al2O3作为Mo催化剂担体的研究   总被引:6,自引:0,他引:6  
魏昭彬  辛勤 《物理化学学报》1994,10(10):931-935
Tio。-AI。oa二元氧化物的制备at艺大体可分为两种.一种是利用液相浸渍或气相沉积方法将Tio。担载在AI。0。上,使Tio。主要覆盖在AI。0。表面上[‘-1另一种是通过Ti盐和AI盐混合溶液共沉淀方法使Tio。和AI。0。均匀混合在一起【‘-’1.不同的制备工艺对Tio。-AI。03的表面结构和表面性质有很大影响问.我们曾报导用TICly蒸气化学气相沉积方法制备出了D02在1川2O3表面呈现十分均匀分布的DoZ一周。03复合氧化物担体*’1.本文进一步考察D0。在周。0。表面的沉积对川。0。孔结构的影响,以及Ti02-A1203作为加氢精制MO催…  相似文献   

10.
(一)卤素(11)氯气的性质和用途。用电子得失或转移来说明氧化-还原反应。漂白粉。氯气的制法。氯化氢。氟、氯、溴、碘和它们的重要化合物。卤素性质的比较。说明:盐酸的性质在初中里讲,本章只讲氯化氢。  相似文献   

11.
In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.  相似文献   

12.
KMnO4-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.  相似文献   

13.
Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.  相似文献   

14.
The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.  相似文献   

15.
A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.  相似文献   

16.
An efficient approach to the synthesis of highly congested di, penta and hexacyclic pyrazoles as well as imidazole fragment containing novel heterocyclic molecule has been developed through a carbanion induced transformation of suitably functionalized 2H-pyran-2-ones, benzo[h]chromene and thiochromeno[4,3-b]pyrans. Due to the presence of fluorescence, we report their prime application metal sensor as off/on switching in ferric ions.  相似文献   

17.
The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp3)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp2)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp2)?H and aliphatic 1,5- and 1,6-C(sp3)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp3)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp2)?H insertion.  相似文献   

18.
The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.  相似文献   

19.
N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).  相似文献   

20.
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