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1.
利用碳糊电极循环伏安法对γ－ＭｎＯ２和β－ＭｎＯ２进行了定量分析，相对于２００．０ｍｇ碳粉的线性范围分别为γ－ＭｎＯ２９．１３～４５．６ｍｇ；β－ＭｎＯ２４．５６～３６．５ｍｇ，在线性范围内测量７次，其ＲＳＤ分别为０．５９％～５．２８％和０％～５．７２％。同时对γ－ＭｎＯ２和β－ＭｎＯ２的混合试样及湘潭电解二氧化锰也进行了定量测定，其平均相对误差分别为２．０１％～１２．４％和１．９６％～７．５２％ 相似文献
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镍与邻羧基苯基重氮氨基偶氮苯的显色反应及其应用 总被引：6，自引：0，他引：6
在乳化剂ＯＰ存在下，于ｐＨ９．７～１０．０的Ｎａ＿２Ｂ＿４Ｏ＿７－ＮａＯＨ缓冲介质中，Ｎｉ￣（２＋）与邻羧基苯基重氮氨基偶氮苯（ＣＤＡＡ）形成组成比为１：２的稳定的红色配合物，其吸收峰波长在５４０ｎｍ，对比度△λ＝１２６ｎｍ，表观摩尔吸光系数为１．９９×１０￣５Ｌ·ｍｏｌ￣（－１）·ｃｍ￣（－１），室温下２０ｍｉｎ内显色反应完全，有色配合物至少稳定１２ｈ。方法线性范围是０～０．２０μｇ／ｍｌＮｉ，检测限为０．０００４μｇ／ｍｌ。在掩蔽剂存在下，方法用于矿样和低合金钢的分析，结果与标准值相符，其ＲＳＤ（ｎ＝６）分别为１．８％和３．１％，标准加入回收率为９５．０％～１０１．２％。 相似文献
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研究结果表明，在混合表面活性剂ＣＴＭＡＢ－吐温－６０存在下的ｐＨ５．７～６．５的缓冲介质中，Ｓｃ（Ⅲ）与４，５－二溴苯基荧光酮（ＤＢＰＦ）形成高灵敏的多元配合物，其ε＿（５９０）＝２．２６×１０￣５Ｌ·ｍｏｌ￣（－１）·ｃｍ￣（－１），组成比为：Ｓｃ：ＤＢＰＦ：ＣＴＭＡＢ＝１：２：４。采用混合表面活性剂使增溶增敏作用更为显著，并加速了显色反应，增强了配合物的稳定性。而Ｎａ＿２ＳＯ＿４的加入能显著地提高体系的灵敏度。Ｓｃ量在０～０．３６ｕｇ／ｍｌ范围内遵守比尔定律。方法可直接测定合成混合稀土中的Ｓｃ，回收率在９８％～１０５％；结合沉淀分离和ＰＭＢＰ萃取分离，实现了地质试样中痕量Ｓｃ的测定。 相似文献
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在十二烷基硫酸钠存在下，于ｐＨ４８～７４的缓冲溶液中，２＿〔２＿（６＿甲基苯并噻唑）偶氮〕＿５＿二乙氨基苯甲酸（６＿Ｍｅ＿ＢＴＡＥＢ）与Ｃｏ（Ⅱ）发生显色反应，形成稳定的蓝紫色络合物，其组成为ｎＣｏ（Ⅱ）∶ｎ６＿Ｍｅ＿ＢＴＡＥＢ＝１∶２，最大吸收波长为６５０ｎｍ，ε为１３８×１０５Ｌ·ｍｏｌ－１·ｃｍ－１，Ｃｏ（Ⅱ）质量浓度在０～０３２ｍｇ／Ｌ时服从比尔定律。方法可直接用于维生素Ｂ１２和含钴分子筛中微量Ｃｏ（Ⅱ）的测定，结果与原子吸收法相符。对于ｗ（Ｃｏ）＝０．８２％的含钴分子筛测定８次，其ＲＳＤ为１３４％。 相似文献
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研究了新合成的ｍｅｓｏ－四（２－磺酸萘基）卟啉（ＴＮＰＳ４）与Ｍｎ＾２＋的显色反应。在ｐＨ８．０的Ｎａ２Ｂ４Ｏ７－ＨＣｌ缓冲溶液中，ＴＮＰＳ４与Ｍｎ＾２＋形成稳定的配合物，最大吸收波长４７０ｎｍ，配合物组成为ＴＮＰＳ４：Ｍｎ＾２＋＝２：１，表观摩尔吸光系数ε＝１．０３×１０＾５Ｌ·ｍｏｌ＾－１·ｃｍ＾－１，线性范围０．０－５．０μｇＭｎ＾２＋／２５ｍｌ。用于化探样品中Ｍｎ的测定，结果令人满意。 相似文献
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甲基异丁基甲酮萃取－石墨炉平台原子吸收法测定地质样品中痕量硒和碲 总被引：1，自引：1，他引：1
样品经ＨＮＯ＿３－ＨＦ－ＨＣｌＯ＿４分解，在５．４ｍｏｌ／Ｌ的ＨＣｌ介质中，以抗坏血酸为还原剂用甲基异丁基甲酮同时萃取样品中的Ｓｅ、Ｔｅ。以Ｐｄ和Ｎｉ作混合基体改进剂，使用自制的涂锆石墨平台直接测定有机相中的Ｓｅ、Ｔｅ。方法的检出限分别为０．２１×１０￣（－９）ｇＳｅ，０．１３×１０￣（－９）ｇＴｅ；测定０．０６ｇＳｅ、０．０３ｇＴｅ的ＲＳＤ（ｎ＝１１）分别为７．０％和８．９％。 相似文献
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二溴羟基苯基荧光酮与铁显色反应及应用 总被引：4，自引：1，他引：4
在溴化十六烷基三甲铵（ＣＴＭＡＢ）存在下，ｐＨ为７０～７４的Ｎａ２Ｂ４Ｏ７ＫＨ２ＰＯ４缓冲溶液体系中，铁与二溴羟基苯基荧光酮（ＤＢＨ＿ＰＦ）形成１∶３的络合物，其最大吸收波长为６００ｎｍ，表观摩尔吸光系数为１１５×１０５Ｌ·ｍｏｌ－１·ｃｍ－１，铁质量浓度在０～０３２ｍｇ／Ｌ符合比尔定律。该方法经硅质砂岩、石灰岩、石膏标样分析验证，结果与标准值相符，ＲＳＤ（ｎ＝５）小于３１％。 相似文献
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Internally-Consistent Thermodynamic Data for Minerals in the System Na2O-K2O-CaO-MgO-FeO-Fe2O3-Al2O3-SiO2-TiO2-H2O-CO2 总被引：14，自引：0，他引：14
Internally consistent standard state thermodynamic data arepresented for 67 minerals in the system Na2O-K2O-CaO-MgO-FeO-Fe2O3-Al2O3-SiO2-TiO2-H2O-CO2.The method of mathematical programming was used to achieve consistencyof derived properties with phase equilibrium, calorimetric,and volumetric data, utilizing equations that account for thethermodynamic consequences of first and second order phase transitions,and temperature-dependent disorder. Tabulated properties arein good agreement with thermophysical data, as well as beingconsistent with the bulk of phase equilibrium data obtainedin solubility studies, weight change experiments, and reversalsinvolving both single and mixed volatile species. The reliabilityof the thermodynamic data set is documented by extensive comparisons(Figs. 4–45) between computed equilibria and phase equilibriumdata. The high degree of consistency obtained with these diverseexperimental data gives confidence that the refined thermodynamicproperties should allow accurate prediction of phase relationshipsamong stoichiometric minerals in complex chemical systems, andprovide a reasonable basis from which activity models for mineralsmay be derived. 相似文献
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W. Johannes 《Contributions to Mineralogy and Petrology》1969,21(4):311-318
The formation of the solid solution series MgCO3-FeCO3 in the system Mg2+-Fe2+-CO 3 2? -Cl 2 2? -H2O has been investigstad between 200° C and 500° C. The experimental results show that the composition of any of these carbonates strongly depends on the temperature: At high temperatures mixed crystals rich in MgCO3 are formed and low temperatures lead to the formation of FeCO3-rich carbonates. Thus, at 200° C a Fe-poor (Mg-rich) solution is in equilibrium with a Fe-rich carbonate. At temperatures higher than 350° C a Fe-rich (Mg-poor) solution coexists with a Fe-poor (Mg-rich) solid phase; see Fig. 1. At 350° C a solution with a mole fractionmFe2+/(mFe2++mMg2+) of 0.20 leads to the formation of magnesite very poor in Fe, whereas at 250° C the same solution is in equilibrium with sideroplesit, containing 80 Mol-% FeCO3, see Figs. 2 and 3. The importance of the experimental results for the formation of deposits of magnesite and siderite is discussed. 相似文献
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A series of stable pentasulfide complexes of the common base metals, Mn, Fe, Co, Ni, Cu and Zn exist in aqueous solutions at ambient temperatures. Pure sodium pentasulfide was prepared and reacted with the divalent cations of Mn, Fe, Co, Ni, Cu and Zn in aqueous solution at ambient temperature. The S52- complexes were found to exist as determined by voltammetric methods.Pentasulfide complexes with compositions assigned as [M(1-S5)] and [M2(- S5)]2+ occur for Mn, Fe, Co and Ni where only one terminal S atom in the S52- binds to one metal (1 = mono-dentate ligand or M-S-S-S-S-S, = ligand bridging two metal centers or M-S-S-S-S-S-M). Conditional stability constants are similar for all four metals with log 1 between 5.3 and 5.7 and log 2 between 11.0 and 11.6. The constants for these pentasulfide complexes are similar to the tetrasulfide complexes and are approximately 0.4–0.8 log units higher than for comparable bisulfide complexes [M(SH)]+ as expected based on the higher nucleophilicity of S52- compared to HS-. Voltammetric results indicate that these are labile complexes.As with the bisulfide and tetrasulfide complexes, Zn(II) and Cu(II) are chemically distinct from the other metals. Zn(II) reacts with pentasulfide to form a stable monomeric pentasulfide chelate, [Zn(1-S5)] with log = 8.7. Cu(II) reacts with pentasulfide to form a complex with the probable stoichiometry [Cu(S5)]2 with log estimated to be 20.2. As with the other four metals, these complexes are comparable with the tetrasulfide complexes. Discrete voltammetric peaks are observed for these complexes and indicate they are electrochemically inert to dissociation. Reactions of Zn(II) and Cu(II) also lead to significant breakup of the polysulfide.The relative strength of the complexes is Cu > Zn > Mn, Fe, Co, Ni. Cu displaces Zn from [Zn(1- S5)] and both Cu and Zn displace Mn, Fe, Co and Ni from their pentasulfide complexes. 相似文献
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Single crystal Raman spectra of pyrite-type RuS2, RuSe2, OsS2, OsSe2, PtP2, and PtAs2 are presented and discussed with reference to the energies of the X-X stretching modes
x-x (A
g, F
g) and the X2 librations
(E, 2Fg). The main results obtained are (i) strong Raman resonance effects, (ii) different sequences for
x-x (A
g) and
(E
g), i.e.,
R_{x_2 } $$
" align="middle" border="0">
for PtP2 and PtAs2 and
R_{x_2 } $$
" align="middle" border="0">
for OsS2, owing to the interplay of intraionic and interionic lattice forces, (iii) greater strengths for the intraionic P-P and As-As bonds compared to the S-S and Se-Se bonds, respectively, and (iv) a strong influegnce of the metal ions on the strength of the X-X bonds.This is contribution LXI of a series of papers on lattice vibration spectra 相似文献
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Gert Hoschek 《Contributions to Mineralogy and Petrology》1974,47(4):245-254
P, T, \(X_{{\text{CO}}_{\text{2}} }\) relations of gehlenite, anorthite, grossularite, wollastonite, corundum and calcite have been determined experimentally at P f =1 and 4 kb. Using synthetic starting minerals the following reactions have been demonstrated reversibly
- 2 anorthite+3 calcite=gehlenite+grossularite+3 CO2.
- anorthite+corundum+3 calcite=2 gehlenite+3 CO2.
- 3anorthite+3 calcite=2 grossularite+corundum+3CO2.
- grossularite+2 corundum+3 calcite=3 gehlenite+3 CO2.
- anorthite+2 calcite=gehlenite+wollastonite+2CO2.
- anorthite+wollastonite+calcite=grossularite+CO2.
- grossularite+calcite=gehlenite+2 wollastonite+CO2.
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A revised equation is proposed to represent and extrapolate the heat capacity of minerals as a function of temperature: C
P=k0+k1
T
–0.5+k2
T
–2+k3
T
–3 (where k1, k20).This equation reproduces calorimetric data within the estimated precision of the measurements, and results in residuals for most minerals that are randomly distributed as a function of temperature. Regression residuals are generally slightly greater than those calculated with the five parameter equation proposed by Haas and Fisher (1976), but are significantly lower than those calculated with the three parameter equation of Maier and Kelley (1932).The revised equation ensures that heat capacity approaches the high temperature limit predicted by lattice vibrational theory (C
P=3R+2VT/). For 16 minerals for which and have been measured, the average C
Pat 3,000 K calculated with the theoretically derived equation ranges from 26.8±0.8 to 29.3±1.9 J/(afu·K) (afu = atoms per formula unit), depending on the assumed temperature dependence of . For 91 minerals for which calorimetric data above 400 K are available, the average C
Pat 3,000 K calculated with our equation is 28.3±2.0 J/(afu·K). This agreement suggests that heat capacity extrapolations should be reliable to considerably higher temperatures than those at which calorimetric data are available, so that thermodynamic calculations can be applied with confidence to a variety of high temperature petrologic problems.Available calorimetric data above 250 K are fit with the revised equation, and derived coefficients are presented for 99 minerals of geologic interest. The heat capacity of other minerals can be estimated (generally within 2%) by summation of tabulated oxide component C
Pcoefficients which were obtained by least squares regression of this data base. 相似文献
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Various members of the KAlSi3O8-BaAl2Si2O8 feldspar series are hydrothermally synthesized. Cellparameters of these are calculated from diffractometer patterns and found to be similar to those of Gay and Roy. A variation diagram is constructed correlating Cn-content and values of ΔFeKα(2θ(111)CaF2—2θ(004)Fsss), which gives $${\text{Mol}}\% {\text{ Cn = 229}}{\text{.83}}\Delta {\text{2}}\theta ---{\text{190}}{\text{.81}}$$ by a least square regression fitting. Phase equilibria relation in the solidus-liquidus-region for the KAlSi3O8-BaAl2Si2O8-H2O system at 1000 kg/cm2 are investigated. It is found to be a case of simple solid solution in a binary system, with reservations at the potassium-rich side of the system. Goranson (1938) gives a temperature of about 1000°C at 1000 kg/cm2 \(P_{{\text{H}}_{\text{2}} {\text{O}}} \) for the incongruent melting of sanidine, but the authors prefer a value around 930°C at the same \(P_{{\text{H}}_{\text{2}} {\text{O}}} \) . Reaction products of starting materials on the join KAlSi2O6-BaAl2Si2O8 and KAlSiO4-BaAl2Si2O8 gave no experimental hint for replacement of K+ by Ba++. 相似文献