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1.
通过对碳单质概念发展历程的考证可知,碳是古代已知的非金属元素。至17—18世纪,随着科学实验的兴起和元素观的发展,金刚石和石墨均被证明为碳的单质,碳单质概念初步形成;20世纪80年代C60的发现及之后碳纳米管、石墨烯和T-碳的发现使人们对碳单质概念有了新认识。在化学教育中,须让学生认识到碳单质概念的发展史是物质的发现史,也是科学思想的演进史和科学方法的发展史。 相似文献
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本文叙述了弗晶型磷-多磷钼酸铵的制备方法,研究了磷-多磷钼酸铵的化学组成,测定了该经合物的离子交换性能,说明多磷酸根部分取代磷酸根所生成的结晶型磷-多磷钼酸铵对铯离子具有良好的离子交换选择性和较高的离子交换容量,是一类新的结晶型无机离子交换剂。 相似文献
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含有零维金纳米球的胶体金,在古埃及就已经被用于制造彩色玻璃,但直到20世纪,人们才对其进行系统的研究。20世纪下半叶,一维金纳米棒的合成及其奇异的光学性质引起了科学家对金纳米颗粒的关注。随后,二维金纳米片、三维金纳米哑铃等金纳米颗粒的相继出现,丰富和发展了金单质的概念。几种新的金单质的发现,构建了从零维到三维的金范式,从而启发人们对“金单质”及其应用进行更加深入的探究。 相似文献
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自18世纪石墨与金刚石的组成被确定为碳元素后,碳单质概念初步形成。然而,20世纪末期,包括C60在内的富勒烯一族的发现突破了人们对碳单质的认识。随后,碳纳米管、石墨烯以及人工合成的T-碳的出现,重新诠释了碳单质的概念。碳单质的新发现,建立了从零维到三维的碳范式,掀开了对“碳单质”研究和应用的新篇章。 相似文献
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乙基罗丹明B—磷钼杂多酸—PVA体系超高灵敏度显色反应的研究 总被引:3,自引:0,他引:3
本文详细研究了乙基罗丹明B-磷钼杂多酸-PVA超高灵敏显色反应,提出了高灵敏测量痕量磷的新的分光光度法。缔合物的最大吸收波长位于584nm处,其表观摩尔吸光系数为1.3×10^6mol^-1.cm^-1。并研究了缔合物的组成和红外光谱,本法直接用于钢样及试剂中痕量磷的测定,获得满意的结果,检测下限达6×10^-7%。 相似文献
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磷原子簇正负离子的激光产生与质谱分析 总被引:2,自引:0,他引:2
原子簇的产生与研究,近年来已成为化学与物理学界兴趣的一个焦点。最近我们在自制的装置上,首次观察到各种大小的磷原子簇,并通过对其正负离子质谱的分析,探讨了其可能的构型。实验装置的原理与详细构造已有另文介绍。本实验选择的激光是Nd:YAG激光器的倍频输出(532nm),聚焦后作用于样品的激光功率密度接近10~7W·cm~(-2)。实验的单质磷样品是多次提纯后的红磷。图1所示的磷原子簇的正负离子质谱由两台飞行时间质谱计同时记录,由连续30次采集的数据平均而成。 相似文献
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Dr. Zhuofeng Hu Luyan Yuan Prof. Zhifeng Liu Dr. Zhurui Shen Prof. Jimmy C. Yu 《Angewandte Chemie (International ed. in English)》2016,55(33):9580-9585
Semiconductive property of elementary substance is an interesting and attractive phenomenon. We obtain a breakthrough that fibrous phase red phosphorus, a recent discovered modification of red phosphorus by Ruck et al., can work as a semiconductor photocatalyst for visible‐light‐driven hydrogen (H2) evolution. Small sized fibrous phosphorus is obtained by 1) loading it on photoinactive SiO2 fibers or by 2) smashing it ultrasonically. They display the steady hydrogen evolution rates of 633 μmol h?1 g?1 and 684 μmol h?1 g?1, respectively. These values are much higher than previous amorphous P (0.6 μmol h?1 g?1) and Hittorf P (1.6 μmol h?1 g?1). Moreover, they are the highest records in the family of elemental photocatalysts to date. This discovery is helpful for further understanding the semiconductive property of elementary substance. It is also favorable for the development of elemental photocatalysts. 相似文献
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Łukasz Albrecht Dr. Anna Albrecht Dr. Henryk Krawczyk Prof. Dr. Karl Anker Jørgensen Prof. Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(1):28-48
240 Years have passed since the discovery of elemental phosphorus. During that time organophosphorus chemistry has emerged as an interesting and exciting field of research. Recently organophosphorus chemistry has been raised to a new level. Organophosphorus compounds have found applications in asymmetric organocatalysis for the synthesis of optically active compounds of synthetic or biological importance. The aim of this review article is to present recent contributions to this developing field of chemistry and to point out synthetic advantages of methodologies developed so far. 相似文献
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Jean-Luc Montchamp 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1-3):66-75
Abstract The vast majority of organophosphorus compounds is currently synthesized from phosphorus trichloride (PCl3), even though the final consumer products do not contain reactive phosphorus–chlorine bonds. In order to bypass phosphorus trichloride, significant interest has been devoted to functionalizing elemental phosphorus (P4, the precursor to PCl3), red phosphorus (Pred), or phosphine (PH3). Yet, other industrial-scale precursors are hypophosphorous derivatives (H3PO2 and its alkali salts), but their use as phosphorus trichloride replacements has been completely overlooked. Here, the case is made for an alternative approach to the industrial synthesis of organophosphorus compounds based on hypophosphites. 相似文献
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N. K. Gusarova S. F. Malysheva S. N. Arbuzova B. A. Trofimov 《Russian Chemical Bulletin》1998,47(9):1645-1652
Data on the reactions of elemental phosphorus and phosphine with electrophilic reagents are described systematically and analyzed.
These reactions occur in the presence of strong bases and yield primary, secondary, and tertiary phosphines and phosphine
oxides.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1695–1702, September, 1998. 相似文献
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B. G. Sukhov N. K. Gusarova S. F. Malysheva B. A. Trofimov 《Russian Chemical Bulletin》2003,52(6):1239-1252
The reveiw surveys and systematizes data on the role of defect formation in activation of red phosphorus. The reactivities of different modifications of elemental phosphorus (viz., white phosphorus, commercial red phosphorus, and red phosphorus containing high concentrations of biographical and induced defects) in inorganic and organic reactions were comparatively analyzed. 相似文献
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A novel β-ketophosphenato ligand bearing a bulky substituent, Tbt(2,4,6-tris[bis(trimethylsilyl)methyl]phenyl), on the phosphorus atom was newly designed and synthesized as a heavier congener of a β-ketoiminato ligand. Rhodium and iridium complexes bearing this new β-ketophosphenato ligand have been synthesized and fully characterized by spectroscopic and elemental analyses together with X-ray crystallographic analyses. The results of NMR spectroscopic studies and the X-ray structural analyses suggested that the β-ketophosphenato ligand has unique electronic features due to the low-coordinated phosphorus atom. Comparison of properties between rhodium β-ketophosphenates 2a,b and rhodium β-ketoiminate 7 revealed the character of the β-ketophosphenato ligand, where the trans influence of the phosphorus atom should be stronger than the nitrogen atom of the β-ketoiminato ligand. 相似文献
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1,3-双芳氧乙酰基-1,3,2-二氮磷杂环戊烷-2-硫(硒)代化合物的合成及除草活性研究 总被引:1,自引:0,他引:1
利用 P( NEt2 ) 3 与双酰胺类化合物在干馏条件下的环缩合反应合成了一系列含双芳氧乙酰基的新型五元磷杂环 ,对所合成的化合物进行了元素分析和谱学表征 .初步生物活性测定表明 ,部分化合物具有优良的选择性除草活性 .合成中首次发现此类磷杂环的 P Se与 P—Se的转化现象 ,通过 X射线单晶衍射确证了产物的结构 ,并发现产物分子间氢键的存在 相似文献
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1791年,英国矿物学家格雷戈尔发现钛矿石并意识到一种新元素的存在。至1795年,普鲁士化学家克拉普罗特进一步预言了该元素,并将之正式命名为钛(Titanium)。1910,美国化学家亨特制取了纯净的钛单质,钛元素的概念正式形成。20世纪20年代以后,钛同位素的发现使人们对钛元素概念有了新认识,并逐渐形成现代钛元素概念。钛元素概念的发展使人们在科学认知上发生了转变,促进了化学元素观的演进。 相似文献
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E. S. Batyeva 《Russian Chemical Bulletin》1993,42(10):1627-1633
This review summarizes the data on the synthesis of various phosphorus-and-sulfurcontaining organic compounds based on the
reactions of elemental phosphorus and sulfur and their derivatives (various types of esters of trivalent phosphorus thioacids)
with a variety of organic compounds.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1706–1711, October, 1993. 相似文献
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通过对硅元素发现历程的考证分析可知,17、18世纪随着科学实验的兴起以及元素观的发展,科学家以实践为基础,运用逻辑思维和直觉思维预见了硅元素的存在;19世纪随着电化学和分析化学的发展,科学家们成功制取无定形硅和晶体硅;20世纪30年代,硅同位素的发现使人们对硅元素的概念有了新认识。总之,随着科学思想的演进和科学方法的发展,硅元素概念的内涵也在不断发展变化。 相似文献