过氧化钠是呈白色还是淡黄色

高中化学教材认为过氧化钠是淡黄色固体,这是一种旧观点。笔者认为过氧化钠是白色固体。钠在空气中燃烧的产物是白色的Na2O、Na2O2和淡黄色的NaO2组成的混合物;钠在空气中燃烧的产物颜色主要是由NaO2的存在引起的,过氧化钠并不是淡黄色物质。所以,应该恢复过氧化钠是白色固体的真相,不能再以讹传讹了。     

从固体化学到凝聚态化学

“凝聚态化学”是化学学科一个新的发展领域,其基本思想是超越分子和理想晶体的界限,多层次地研究物质的组成、结构、性质、制备以及它们之间的关系。本文简要回顾了从固体物理到凝聚态物理的历史以及固体化学的发展历史,分析了固体化学的学科特点,指出固体化学的发展必然孕育着“凝聚态化学”的形成,同时指出,化学学科中的多个领域也都会将“凝聚态化学”作为自己的发展方向。建议了从固体化学向“凝聚态化学”发展的途径:完善固体化学学科的知识体系,拓展固体化学的知识范围,创造“凝聚态化学”的标志性成果。最后强调,与凝聚态物理学家密切合作,共建“凝聚态科学”大厦。     

催化裂化汽油固体碱预碱洗的研究──负载固体碱对硫化氢的吸附过程分析

以活性炭为载体,碱金属化合物为活性组分,制备出负载固体碱,对其吸附硫化氢性能进行了研究。结果表明,此类固体碱吸附硫化氢能力较强,在固体碱孔外主要进行化学吸附,在固体碱孔内以物理吸附为主,化学吸附和物理吸附能力分别与固体碱、固体碱孔内所负载活性组分的量有关     

催化裂化汽油固体碱预碱洗的研究：负载固体碱对硫化氢的吸附过？…

以活性炭为载体,碱金属化合物为活性组分,制备出负载固体碱,对其吸附硫化氢性能进行了研究。结果表明,此类固体碱吸附硫化氢能力较强,在固体碱孔外主要进行化学吸附,在固体碱孔内以物理吸附为主,化学吸附和物理吸附能力分别与固体碱、固体碱孔内所负载活性组分的量有关。     

第二届全国无机固体化学和合成化学学术会议通知

中国化学会无机专业委员会拟定于1988年7月4日至了月9日在合肥中国科学技术大学召开第二届个国无机固体化学和合成化学会议。1.征文内容:缺陷化学、固相反应、固体表面和界面化学、固相中的扩散、无机固体新材料、复合金属氧化物、极端条件下的无机合成。固体化学中的制备方法、固态初质的分析和表征等。2.将论文详细摘要(1500字左右)一式二份寄北京大学化学系苏勉曾、或合肥中国科技大学材料系     

从溶液中获得含有功能基的碳纳米管

从溶液中获得含有功能基的碳纳米管印度科学家Ｒａｏ等人将碳纳米管在硫酸－硝酸中回流，得到了一种澄清的无色溶液，除去溶剂之后，剩余物为白色固体。扫描电镜的观测表明，这种白色固体具有类似于碳纳米管的结构，且大部分呈聚集状态。能谱、红外及核磁共振碳谱均表明这...     

《固体化学》书讯和讲习班信息

由于近代高技术的发展,材料科学与化学发生越来越深入的渗透,固体化学应运而生。现代技术所需要的各种材料的研制包括设计、合成、改性、成型和检测,都要求固体化学为之提供理论和方法。而对固体的研究方法、结构与性能关系等方面的探索又需要借鉴于现代物理、固体物理、晶体物理等方面的知识,所以固体化学所包含内容与传统化学知识有相当大的差     

《固体化学导论》评介

由苏勉曾教授编著,北京大学出版社出版的《固体化学导论》一书,是国内第一部固体化学教科书。该书既可作为化学、物理、材料科学及工程学等专业用书,也可供这些方面的教师、研究人员和技术人员参考。全书共分十二章,约35万字,共五大部分:晶体的基本结构形式,包括第二、三、四章;固体中的点缺陷及运用电子、空穴和缺陷运动及能带理论,论述固体中的扩     

化学杀雄剂均三嗪二酮的质谱测试

<正> 均三嗪二酮是我所研制的新化学杀雄剂,应用于抑制小麦或水稻的雄芯发育,以配制优良的杂交良种。均三嗪二酮的质谱数据目前国内外尚未见报道,我们采用电子轰击离子源(EI)和化学电离源(CI)的方法,确定了均三嗪二酮的分子离子峰,并对其质谱图作了解析,为化学杀雄剂均三嗪二酮的合成工作提供了重要质谱数据。一、实验条件样品Ⅰ:熔点223～224℃白色结晶固体仪器:MAT—311A EI源     

固相配位化学反应

一、引言固相配位化学反应研究的是配合物在低热温度(室温—200℃)下的固相反应,它是介于固体化学与配位化学之间的一门边缘学科。近二十年来,一些新技术新学科的兴起,要求越来越多具有特殊性能的固体材料,研究它们的合成、结构、性质和开发应用是固体化学的任务。传统配位化学主要研究溶液中配位化合物的合     

利用手持技术改进测定乙醇分子结构实验

利用压强传感器代替排水集气法,改进测定乙醇分子结构实验的仪器装置,并探索最佳反应条件。另外,设计两个空白实验,结合压强变化曲线对实验误差进行相关讨论。     

光谱仪测试范围的扩展

由于石化行业的生产需要，其材质的使用具有多样性和广泛性，经常会出现顾客委托的测试样品的一个或几个元素跨越光谱仪现有测试程序测量范围的情况。本法通过对光谱仪测试原理的认识，根据光谱仪的测试能力及标样的采集，实现了一个或几个元素测量范围的扩展，并对其测量的影响因素进行了研究。     

Influence of viscosity of medium on processes of oxygen quenching of excited states of mesoporphyrin

The oxygen quenching rate constants for singlet and triplet excited states of the dimethyl ester of mesoporphyrin IX increase with decreasing viscosity of the medium and reach a maximum at a viscosity of approximately 0.4 mPa·sec, after which the rate constants begin to decrease. The drop in rate constant with increasing fluidity of the medium may be related to a nonequilibrium character of the elementary act in the interaction of the reactants in the solvent cage. In viscous media such as isopropyl alcohol, isobutyl alcohol, and isoamyl alcohol, the reaction radius is greater than the sum of the radii of the reacting particles. The long-range character of these processes is due to the relatively weak dependence of the quenching probability on distance.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 25, No. 2, pp. 161–167, March–April, 1989.     

Dichroism of absorption and polarization of phosphorescence of molecules of the closed form of nitrobenzospirothiopyran

The spectral-polarization characteristics of absorption and phosphorescence of molecules of the initial form of nitro-substituted indolinospirobenzothiopyran were studied in oriented polyethylene films and in solutions with different polarity. An oscillator model of the electron transitions responsible for the formation of absorption and luminescence spectra was suggested. It was established that the principal differences in the spectral and photophysical properties of the compound studied and its oxygen-containing analog are associated with the fact that the electronegativity of the S atom is lower than that of the O atom. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1143–1146, June, 1997.     

Neutral diterpenoids of oleoresins of five species of conifers of Transcarpathia

The compositions of the neutral diterpenoids of the oleoresins of five species of conifers growing in the Transcarpathia have been studied. It has been found that the oleoresins ofAbies alba M.,Larix decidua M., andPicea excelsa L. contain more than 50% of neutral diterpenoids. The group and qualitative compositions of the oxygen-containing diterpenoids have been determined. In the oleoresins ofAbies alba,Picea excelsa, andPicea abies tertiary alcohols — cis-abienol and isocembrol — predominate, while inLarix decidua the main component is the hydroxy ester larixyl acetate. Primary alcohols related to the resin acids have been found in all the oleoresins investigated. Features of the distribution of diterpenoids according to the species of conifers have been revealed. The results obtained are necessary for the chemotaxonomy of conifers of the family Pinceae.Novosibirsk Institute of Organic Chemistry, Siberian Branch, Academy of Sciences of the USSR. Translated from Khimiya Prirodynkh Soedinenii, No. 6, pp. 812–816, November–December, 1988.     

Determination of heats of detonation and influence of components of composite explosives on heats of detonation of high explosives

The heats of detonation of 20 simple high explosives and explosive mixtures were determined by means of an adiabatic detonation calorimeter designed by the authors. The results indicated that the performance of the instrument was reliable and the experimental data were very accurate. For explosive mixtures, there was a linear accumulative relationship between the heats of detonation of the explosive mixture and its components. Accordingly, the heats of detonation of explosive mixtures could be calculated directly from the heats of detonation of simple explosives and the characteristic heats of other components. The experiments showed that the gold or brass shell of the cylindrical charge could be substituted by a thick-walled porcelain shell, which had the advantage of cheapness.

     

物质分配系数的测定实验改进

实验教学目的是从解决实际问题出发,以实验技术训练和实验设计思想培养为目标。介绍了将单一的物质分配系数测定实验改进为综合实验,提高了实验效果及实验资源利用率。     

Calculation of enthalpies of hydrogenation of hydrocarbons

Sets of hydrogen molecule equivalents have been developed which permit the calculation of hydrogenation of different types of carbon-carbon bonds from ab initio total energies (3-21G and 6-31G* basis sets, and, to a more limited extent, for MP2/6-31G* data) of reactants and products. The calculated enthalpies of hydrogenation are in good agreement with experiment for unstrained molecules, with average errors on the order of 2 kcal/mol. The 6-31G* equivalents allow the enthalpies for strained molecules to be calculated accurately, but the 3-21G equivalents do not. The equivalents for both basis sets have been tested by calculating the enthalpies of hydrogenation of carbon-carbon bonds in nitrogen- and oxygen-containing organic molecules, free radicals, and classical carbocations. The results are in good agreement with experiment in most cases.