电感耦合等离子体原子发射光谱(ICP-AES)法测定再生锌原料中铜、铅、铁、铟、镉、砷、钙、铝

采用硝酸、盐酸、氢氟酸(氟化氢铵)、高氯酸分解样品,电感耦合等离子体原子发射光谱法测定了再生锌原料中铜、铅、铁、铟、镉、砷、钙、铝的量。其测定范围:ω(Cu):0.01%～0.60%;ω(Pb):0.10%～5.00%;ω(Fe):0.10%～5.00%;ω(In):0.0100%～0.200%;ω(Cd):0.010%～3.00%;ω(As):0.10%～2.00%;ω(Ca):0.10%～10.00%;ω(Al):0.10%～4.00%。各元素的加标回收率为93%～113%。方法准确、快速、可靠,适用于再生锌原料中铜、铅、铁、铟、镉、砷、钙、铝量的同时测定。     

电感耦合等离子体发射光谱测定钼铝合金中硅含量的方法研究

采用王水、氢氟酸在180℃加热条件下溶解试样,全面分析了硅元素的212.412、221.667、251.611、252.851、288.158 nm五条分析谱线的受干扰情况,最终选择了灵敏度和信噪比较高、受钼基体干扰程度较小的Si 288.158 nm为分析谱线。使用多谱线拟合(MSF)技术建立了Si 288.158 nm的光谱校正模型,通过校正模型对样品检测信号峰进行了校正,消除了基体钼(Mo 288.137 nm)的光谱干扰,建立了电感耦合等离子体发射光谱法(ICP-OES)测定钼铝合金中硅含量的方法。该方法在0.10～5.00 mg/L范围内(对应固体样品中硅的质量分数范围为0.010%～0.50%),硅的工作曲线线性关系良好,相关系数为0.9995;方法检出限和定量限分别为23μg/g和76μg/g;对3个不同含量的钼铝样品中的硅含量进行了测定,测定结果的相对标准偏差(RSD)在0.76%～1.36%之间,加标回收率在98.0%～106%范围,与标准(YS/T 1075.3-2015)中钼蓝分光光度法的测定结果一致。     

X射线荧光光谱法测定电解锰中锰、硅、磷和铁含量

熔融制样X射线荧光光谱法测定电解锰中锰、硅、磷和铁含量。用熔融后的四硼酸锂制作铂金坩埚保护层,以BaO2做氧化剂,在马弗炉内通过逐渐升温来氧化电解锰,然后熔融制取玻璃熔片,用X射线荧光(XRF)光谱法分析电解锰中锰、硅、磷和铁含量。锰、硅、磷和铁的相对标准偏差RSD分别为0.23%、2.82%、0.31%和0.53%。与其它分析方法比较,其结果更稳定。有效消除了电解锰熔融制样过程中的坩埚腐蚀问题,分析误差可完全控制在国家相关标准允许的范围内,实现了电解锰中各元素的快速准确测定。     

碳素锰及硅锰合金中磷量的快速测定

钢铁中都含有磷,它是由冶炼原料及燃料带入,而磷的存在使钢冷脆并降低钢的冲击性及韧性。碳素锰及硅锰铁是钢铁的冶炼原料之一,因此准确测定其中磷的含量对钢铁生产有着重要的意义。 目前碳素锰及硅锰铁中磷的测定,国家标准方法采用硝酸和氢氟酸分解试样,加入高氯酸冒烟使磷氧化为正磷酸,使之生成磷钼酸铵沉淀,用中和滴定法测定磷量,或者将磷氧化为正磷酸后,以亚硫酸氢钠将铁还原,加入钼酸铵及硫酸肼使之反应,然后用钼蓝光度法测定磷量。有用抗坏血酸还原磷铋钼蓝比色法,也有用磷钒钼黄光度法。这些方法虽然准确度高,但分析周期长,成本高,较难适应生产的需要。为适应生产发展,提高分析速度,在文献[1～4]的基础上,将试样溶解完全后,不经分离,直接用氟化钠-氯化亚锡钼蓝吸光度法快速测定碳素锰及硅锰铁中的磷量。方法简便,稳定性较好,可满足于生产检验。本法测量范围0.10％～0.46％,相对标准偏差小于35％。     

锰硅合金中硅的测定

锰硅合金可作为炼钢脱氧剂。根据合金中含锰和含硅量不同 ,分为各种牌号的合金 ,所以合金中含硅量的数据也要求准确。锰硅合金中硅的测定 ,原采用锰铁合金中硅的分析方法进行测定 ,因锰硅合金中硅含量较锰铁合金中硅含量高 ,试样不易溶解完全 ,锰与铁也不易分离完全 ,至使分析结果偏高。后又采用铁 (镍 )坩埚碱熔 ,试样虽溶解完全 ,但在溶样过程中试样易溅出 ,造成损失 ,且碱熔时易将铁 (镍 )坩埚腐蚀而转入试液中 ,洗二氧化硅沉淀时难于洗净 ,至使结果偏高。为此 ,经试验 ,采用盐酸 -过氧化氢溶样 ,动物胶重量法测定锰硅合金中的硅 ,经试验…     

ICP-AES法测定镍铬铝钇硅合金中的铝、钇、硅

建立电感耦合等离子体发射光谱测定镍铬铝钇硅合金中铝、钇、硅含量的方法。采用盐酸–硝酸(6∶1)混合酸溶解样品,通过基体匹配消除基体镍的干扰,铝、钇、硅的分析谱线分别为394.401,371.029,251.611 nm。铝、钇、硅的质量浓度分别在1.00～30.00,1.00～20.00,1.00～30.00 mg/L范围内与其发射强度呈良好的线性,线性相关系数均大于0.999,检出限分别为0.013,0.002,0.064 mg/L。加标回收率为94.60%～103.51%,测定结果的相对标准偏差均小于2%(n=11)。该方法快速、稳定,可用于实际生产中镍铬铝钇硅中铝、钇、硅元素的测定。     

氢氧化钠熔融法分解硅铝铁测定硅

硅铝铁作为一种硅系铁合金 ,以其优异的脱氧、脱硫能力 ,较高的合金利用率 ,正广泛应用于冶金行业中 ,但其分析方法仍无国家标准。对其硅的分析一般均衍用硅铁中硅的分析方法重量法[1] 和比色法 [2 ] 。重量法中采用过氧化钠熔融法 ,该方法对坩埚的腐蚀严重 ,使用几次坩埚即被蚀穿。而且过氧化钠价格昂贵 ,性质不稳定不易保存。比色法采用硝酸 -氢氟酸溶样 ,样品不易溶解完全 ,造成分析结果偏低。经过理论和试验证实 ,采用氢氧化钠熔融法[3] 分解硅铝铁 ,该方法对坩埚腐蚀小 ,而且试剂便宜 ,适应性好。1　试验方法称取氢氧化钠 4g于镍 (铁 )…     

原子吸收光谱法测定硅铝铁复合脱氧剂中铅锌铜

采用原子吸收法测定硅铝铁中杂质元素铅，锌和铜，用硝酸，氢氟酸溶样去硅，加高氯酸去氢氟酸，方法简便，通过试样分析，结果满意，加标准回收率为９９％～１０３％，此法可作为硅铝铁中铅，锌，铜分析的常用方法。     

电感耦合等离子体原子发射光谱(ICP-AES)法测定NiCrAlYSi合金中铝、硅、铁、钴、钛

用盐酸、硝酸及氢氟酸溶解样品,采用基体匹配法配制标准溶液系列以消除基体效应的影响,选择Al 394.401nm、Si 251.611nm、Fe 259.940nm、Co 238.892nm、Ti 337.280nm为分析线,使用电感耦合等离子体原子发射光谱(ICP-AES)法测定NiCrAlYSi合金中的铝、硅、铁、钴、钛。Al的质量分数在0.10%~15%、Si的质量分数在0.01%~6.0%、Fe、Co、Ti的质量分数在0.005%~0.50%时,各元素质量分数与对应的发射强度呈线性,线性相关系数不小于0.999 5;方法中各元素检出限为0.0005%~0.0020%;结果的相对标准偏差为0.46%~3.7%;加标回收率为90.0%~104%。方法简单、快速,结果令人满意。     

硅青铜和铝青铜光谱分析标准物质的研制

研制了2种硅青铜和10种铝青铜光谱分析标准物质。该标准物质以高纯铜为主料、按杂质元素的性质分批分期加入Cu-Fe、Ni、Si、Pb、Sn、Cu-As、Cu-S、Zn、Mn、Cr、Al、Cu-P等12种成分，采用250 kg中频感应炉冶炼，半连续铸造，2 000吨水压挤压机挤压而成，确保了标准物质的均匀性。8家权威实验室用准确可靠的分析方法确定了13种元素的标准值和不确定度。元素定值区间分别为：Cu 80.92%～95.77%,Pb 0.000 2%～0.001 5%,Zn 0.001 1%～0.034%,P0.000 4%～0.006 1%,Fe0.027%～4.09%,Sn0.001 2%～0.033%,As0.000 15%～0.000 4%,Al7.69%～10.26%,Mn0.055%～2.10%,Ni0.030%～4.48%,Si0.008 4%～3.31%,Cr0.012%～0.026%,S0.000 8%～0.000 9%。定值结果的扩展不确定度为0.000 04%～0.10%(k=2)。该标准物质的均匀性与稳定性良好，定值结果准确，已被国家市场监督管理总局批准为国家级标...     

From ephemers to monomers, oligomers and polymers. New methods for the generation and transformation of silanones

New efficient routes to the generation of silanones at relatively low temperatures are based on the following reactions:

1. (1) reaction of linear and branched perhydrocarbyldisiloxanes and oligosiloxanes, and of some of their C-functional derivatives, with gallium or indium iodides or bromides;

2. (2) reaction of hydrocarbylchlorosilanes R_4−nSiCl_n (n = 2–4) and SiCl₄ with dimethylsulphoxide (with or without Mg or Zn);

3. (3) Autodecomposition of organosilicon compounds containing and groups;

4. (4) reaction of R_4−nSiCl_n with metal oxides of high redox potential (with or without the presence of CH₃CN).

Insertions of dialkylsilanones into Si---O---Si and Si---O---C linkages as well as into the Si---Cl bond have been studied.     

The Synthesis and Molecular Structure of the First Two-Coordinate,Dinuclear σ-Bonded Mercury(I) RHgHgR Compound

A linear Si-Hg-Hg-Si arrangement and a Hg–Hg distance of 265.69 pm are exhibited by the first two-coordinate, dinuclear σ-bonded organomercury(I ) compound 1. It was formed unexpectedly in the reaction of two equivalents of the silane (Me₃SiMe₂Si)₃SiH with tBu₂Hg. In contrast if the reagents are allowed to react in a 1:1 ratio the expected mercury(II ) compound (Me₃SiMe₂Si)₃SiHgtBu is obtained.     

Dimeric and trimeric diorganosilicon chalcogenides (PhRSiE)2,3 (E = S, Se, Te; R = Ph, Me)

Ph₂SiCl₂ and PhMeSiCl₂ react with Li₂E (E = S, Se, Te) under formation of trimeric diorganosilicon chalcogenides (PhRSiE)₃ (R = Ph: 1a-3a, R = Me: cis/trans-4a (E = S), cis/trans-5a (E = Se)). In case of E = S, Se dimeric four-membered ring compounds (PhRSiE)₂ (R = Ph: 1b-2b, R = Me: cis/trans-4b (E = S), cis/trans-5b (E = Se)) have been observed as by-products. 1a-5b have been characterized by multinuclear NMR spectroscopy (¹H, ¹³C, ²⁹Si, ⁷⁷Se, ¹²⁵Te). Four- and six-membered ring compounds differ significantly in ²⁹Si and ⁷⁷Se chemical shifts as well as in the value of ¹J_SiSe.The molecular structures of 2a, 3a and trans-5a reported in this paper are the first examples of compounds with unfused six-membered rings Si₃E₃ (E = Se, Te). The Si₃E₃ rings adopt twisted boat conformations. The crystal structure of 3a reveals an intermolecular Te-Te contact of 3.858 Å which yields a dimerization in the solid state.     

Silylated β-enaminones as precursors in the regioselective synthesis of silyl pyrazoles

Silyl β-enaminones have been synthesized by reductive cleavage of 5-silyl, 3-, 4- and 5-silylmethylisoxazoles.These versatile synthons bearing different silyl groups in various positions of the enaminoketonic system are of great interest in the regioselective synthesis of 3- or 5-silylpyrazoles and 3-, 4- or 5-silylmethylpyrazoles, which can serve as building blocks in heterocyclic chemistry.     

Preparation, crystal structure, and reactivity of bis {tris(trimethylsilyl) methyl} magnesium

Heating of the lithium magnesate [Li(THF)₂(μ-Br)₂Mg(Tsi)(THF)] (Tsi = (Me₃Si)₃C) under vacuum gives the dialkylmagnesium compound Mg(Tsi)₂, the first two-coordinate magnesium derivative to have been structurally characterized in the solid state. The compound is remarkably thermally stable, not decomposing (or melting) when heated to 350°C. It has a very low reactivity, failing to react in toluene with, for example, CO₂, Me₃SiCl, Me₂SiHCl, MeI, BCl₃ or CH₃COCl, and even with neat CH₃COCl at its boiling point. It does react, though fairly slowly, with I₂ in toluene to give TsiI, and more rapidly with Br₂ to give TsiBr, and with an excess of PhSO₂Cl in toluene at 1OO°C to give TsiCl. It decomposes quickly in the air, and reacts readily with MeOH in toluene to give TsiH without formation of detectable amounts of the intermediate TsiMgOMe, and with O₂ in toluene.     

Chlor-, Brom- und Iodtrisilane: Synthesen und Si-Kernresonanzspektren

Halogenated trisilanes X_nSi₃H_8−n with X = Cl, Br, I and n = 2–7 as well as the tetrasilanes H₂XSiSiX₂SiX₂SiX₂H have been prepared by dearylation of appropriate aryltrisilanes and aryltetrasilanes (aryl = phenyl, p-tolyl) with either liquid or gaseous hydrogen halides. The compounds have been characterized with elemental analysis as well as ²⁹Si NMR spectroscopy.     

Struktur und Eigenschaften von Ba2Mg3Si4, einer Zintl-Phase mit planaren Si6-Einheiten

Structure and Properties of Ba₂Mg₃Si₄, a Zintl Phase with Planar Si₆ Units Within the scope of the investigations on the phase system Ba/Mg/Si a new ternary Zintl phase of the composition Ba₂Mg₃Si₄ was found and structurally characterized. The silicon substructure is built up of Si₂ pairs and a new type of Zintl anion, a planar Si₆ chain. Temperature dependent measurements of the electric conductivity and the magnetic susceptibility show a metallic behavior. Accompanying quantumchemical investigations on the base of the LMTO-ASA method confirm these results and allow an insight in the present bond situation.     

Theoretical Investigation of the Solid State Reaction of Silicon Nitride and Silicon Dioxide forming Silicon Oxynitride (Si2N2O) under Pressure

The high‐pressure behavior of Si₂N₂O is studied for pressures up to 100 GPa using density functional theory calculations. The investigation of a manifold of hypothetical polymorphs leads us to propose two dense phases of Si₂N₂O, succeeding the orthorhombic ambient‐pressure polymorph at higher pressures:a defect spinel structure at moderate pressures and a corundum‐type structure at very high pressures. Taking into account the formation of silicon oxynitride from silicon dioxide and silicon nitride and its pressure dependence, we propose five pressure regions of interest for Si₂N₂O within the pseudo‐binary phase diagram SiO₂‐Si₃N₄: (i) stability of the orthorhombic ternary phase of Si₂N₂O up to 6 GPa, (ii) a phase assemblage of coesite, stishovite, and β‐Si₃N₄ between 6 and 11 GPa, (iii) a possible defect spinel modification of Si₂N₂O between 11 and 16 GPa, (iv) a phase assemblage of stishovite and γ‐Si₃N₄ above 40 GPa, and (v) a possible ternary Si₂N₂O phase with corundum‐type structure beyond 80 GPa. The existence of both ternary high‐pressure phases of Si₂N₂O, however, depends on the delicate influence of configurational entropy to the free energy of the solid state reaction.     

Si6, Si14, and Si22 Rings in Iodide Silicides of Rare Earth Metals

A new class of compounds containing layers of Si _n Zintl polyanions is represented by the silicides MISi (M=La, Ce, Pr), La₄I₃Si₄, and La₅I₃Si₅ (a section of the structure is shown below). Their structures contain Si₆ and the previously unknown Si₁₄ and Si₂₂ rings, which are condensed into layers. The Si atoms are coordinated in a trigonal-prismatic fashion by M atoms to give M-(SiSi)-M slabs that are bonded to one another through I atoms. An extensive chemistry of halide silicides similar to that of the carbide halides of the rare earth metals can be expected.     

β-Carbonylsilanes with a silacyclohexane skeleton and additional C-functionalized organyl groups at the silicon atom: synthesis, reactivity, and NMR-spectroscopic characterization

A series of novel β-carbonylsilanes, with a silacyclohexane skeleton and additional C-functionalized organyl groups at the silicon atom, were synthesized, their reactivity was explored, and they were structurally characterized by multinuclear NMR spectroscopy. The aim of these investigations was to provide the basis for the development of novel silicon-based drugs containing a silacyclohexane skeleton, with a CH₂C(O)R substituent and an additional C-functionalized organyl group at the silicon atom.