无水钾镁矾类复盐(A＋)2Cd2(SO4)3的热化学

The standard molar formation enthalpies of (A＋)2Cd2(SO4)3[A＋ is NH＋ 4 or K＋] are determined from the enthalpies of dissolution (ΔsHm) of [(A＋)2SO 4(s)＋2CdSO4(s)] and (A＋)2Cd2(SO4)3(s) in twice distilled water or 3 mol•L－1 HNO3 solvent respectively,at 298.2 K,as:ΔfHm [(NH4)2Cd2(SO4)3,s,298.2K]=－3031.74±0.08 kJ•mol－1ΔfHm [K2Cd2(SO4)3,s,298.2K]=－3305.52±0.17 kJ•mol－1     

无水钾镁矾类复盐(A~ )_2Cd_2(SO_4)_3的热化学

The standard molar formation enthalpies of (A＋ )2Cd2(SO4)3[A＋ is NH＋ 4 or K＋ ] are determined from the enthalpies of dissolution (Δ SHm) of [(A＋ )2SO4(s)＋ 2CdSO4(s)] and (A＋ )2Cd2(SO4)3(s) in twice distilled water or 3 mol· L－ 1 HNO3 solvent respectively,at 298.2 K,as: Δ fH m[(NH4)2Cd2(SO4)3,s,298.2K]=－ 3031.74± 0.08 kJ· mol－ 1 Δ fH m[K2Cd2(SO4)3,s,298.2K]=－ 3305.52± 0.17 kJ· mol－ 1     

复盐K2Zn(IO3)4·2H2O的热化学研究

The standard enthalpy of formation (Δ_fH^?_m［K₂Zn(IO₃)₄·2H₂O,s,298.2K］=-2210.68 kJ·mol^-1) of a double salt K₂Zn(IO₃)₄·2H相似文献   

复盐K2Mg(IO3)4 2H2O的热力学性质

由于碱金属碘酸盐晶体在电学性质的利用上有重要价值和发现碘酸盐晶体非线性性质［‘］,七十年代以来,Vinogradov等对碘酸盐-碘酸-水系统发生了极大的兴趣,做了大量研究工作［’－‘］,发现在碘酸盐．碘酸一水三元体系里有碘酸盐复盐K2M（IO3）4·2H2O（M＝Mn2＋、Co2＋、N     

SrB4O7·3．5H2O的合成、表征与热化学研究

合成了一种新型碱土金属硼酸盐SrB4O7·3．5H2O,并对它进行了化学分析、红外光谱（IR）、X射线衍射（XRD）及热分析（TC—DTA）等一系列物相鉴定与表征。通过设计热力学循环,利用微热量计测定了SrB4O7·3．5H2O溶解于约1mol·L^-1 HCl水溶液中的摩尔溶解焓,再结合H3BO,在HCl（aq）的摩尔溶解焓,Sr（OH）2·8H2O（s）溶解于[HCl（aq）＋H3BO3（aq）]的摩尔溶解焓,以及H2O（1）、Sr（OH）2·8H2O（s）与H3BO3（s）的标准摩尔生成焓,得到了SrB4O7·3．5H2O的标准摩尔生成焓为-（4435．15±3．30）kJ·mol^-1。     

SrB4O7·3.5H2O的合成、表征与热化学研究

合成了一种新型碱土金属硼酸盐SrB4O7·3.5H2O,并对它进行了化学分析、红外光谱(IR)、X射线衍射(XRD)及热分析(TG-DTA)等一系列物相鉴定与表征.通过设计热力学循环,利用微热量计测定了SrB4O7·3.5H2O溶解于约1 mol·L-1HCl水溶液中的摩尔溶解焓,再结合H3BO3在 HCl(aq)的摩尔溶解焓,Sr(OH)2·8H2O(s)溶解于[HCl(aq)+H3BO3(aq)]的摩尔溶解焓,以及H2O(l)、Sr(OH)2·8H2O(s)与 H3BO3(s)的标准摩尔生成焓,得到了SrB4O7·3.5H2O的标准摩尔生成焓为–(4435.15± 3.30)kJ·mol–1.     

复盐Zn2HIO6• 1.25H2O的热化学研究

由于高碘酸盐及其复盐晶体具有优良的电学性能和抗腐蚀性能,在分析上也很有应用价值［１］三元相高碘酸盐－高碘酸－水系统早在６０年代就引起了人们的兴趣,Ｄｒａｔｏｖｓｋｙ等人对它进行了大量的研究［２－５］．八十年代Ｎａｂａｒ等人用新的方法合成了几种新的高碘...     

水合偏硼酸钾的热化学研究

Hydrated potassium monoborate(KBO₂·4/3H₂O) was obtained from an aqueous solution in a mole ratio of K₂O∶B₂O₃=2∶1 and characterized by powder X-ray diffraction(XRD), infrared spectroscopy(FT-IR) and Raman spectroscopy. The enthalpy of solution of hydrated potassium monoborate, KBO₂·4/3H₂O, in approximately 1mol·dm^-3 aqueous hydrochloric acid was determined. Together with the previously determined enthalpies of so-lution of H₃BO₃ in approximately 1mol·dm^-3 HCl(aq) ,and of KCl in aqueous(hydrochloric acid+boric acid), the standard molar enthalpy of formation of -(1411.11±0.84)kJ·mol^-1 for KBO₂·4/3H₂O was obtained from the standard molar enthalpies of formation of KCl(s), H₃BO₃(s), and H₂O(l). The standard molar entropy of formation of -422.94J·K^-1·mol^-1 and standard molar entropy of 163.47J·K^-1·mol^-1 for KBO₂·4/3H₂O were calculated from the thermodynamic relations. A group contribution method is applicable to KBO₂·4/3H₂O.     

烟酸钠Na(C6H4NO2)(s)的低温热容和热化学

选择分析纯烟酸和无水醋酸钠作为反应物, 用室温固相合成方法合成了无水烟酸钠. 利用FTIR和X射线粉末衍射等方法进行了表征, 利用化学分析和元素分析确定其组成为Na(C6H4NO2). 用精密自动绝热热量计测量其在78~400 K温度区间的低温热容. 研究结果表明, 该化合物在此温度区间无热异常现象发生. 用最小二乘法将实验摩尔热容对温度进行拟合, 得到热容随温度变化的多项式方程. 用此方程进行数值积分, 得到在此温度区间每隔5 K的舒平热容值和相对于298.15 K时的热力学函数值. 在此基础上, 通过设计合理的热化学循环, 选用1 mol/L NaOH溶液作为量热溶剂, 利用等温环境溶解-反应热量计分别测得固相反应的反应物和产物在所选溶剂中的溶解焓, 得到固相反应的反应焓. 最后, 计算出无水烟酸钠的标准摩尔生成焓为: ΔfHm0[Na(C6H4NO2), s]=-(548.96±1.11) kJ/mol.     

四水氯化锰与对甲基苯胺配位反应的热化学研究

用溶解量热法测定聚凝相反应的焓变,并进一步得到指定物质未见报道的标准生成焓数据,是一种较准确的研究手段。所得到结果可完善物质的标准热力学性质,满足化学研究与应用的需要。本文选择氯化锰（NnCl2.4H2O)与对甲基苯胺（CH3C6H4NH2,简称p-tol)进行反应,合成了配合物Mn(p-tol)2Cl2。用新型的具有恒定温度环境的反应热量计^[1],以溶解量热法^[2,3],用一定比例的HCl(3.0mol.L^-1)与无水乙醇的合溶液作为量热溶剂,分别测定了反应物,产物的溶解熔,设计了一个新的热化学循环,得到了配位反应的反应焓,并计算出了配合物Mn(p-tol)2Cl2的标准生成焓。     

Thermodynamics of Silicon Nitride. Standard molar enthalpy of formation of amorphous Si3N4 at 298.15 K

The standard molar enthalpy of formation Δ_f H _m ⁰=–760±12 kJ for amorphous silicon nitride a-Si₃N₄ has been determined from fluorine combustion calorimetry measurements of the massic energy of the reaction: a-Si₃N₄(s)+6F₂(g)=3SiF₄(g)+2N₂(g). This value combined with Δ_f H _m ⁰= –828.9±3.4 kJ for a-Si₃N₄ indicates that determined for the first time molar enthalpy change for the transition from amorphous to α-crystalline form Δ_trs H _m ⁰=69±13 kJ is very evident, in spite of its large uncertainty range resulting from impurity corrections. This revised version was published online in July 2006 with corrections to the Cover Date.     

Thermochemistry of rare earth complexes [Ln(Ala)2(Im)(H2O)](ClO4)3 (Ln=Pr, Gd)

The two complexes, [Ln(Ala)₂(Im)(H₂O)](ClO₄)₃ (Ln=Pr, Gd), were synthesized and characterized. Using a solution-reaction isoperibol calorimeter, standard enthalpies of reaction of two reactions: LnCl₃⋅6H₂O(s)+2Ala(s)+Im(s)+3NaClO₄(s)=[Ln(Ala)₂(Im)(H₂O)](ClO₄)₃(s)+3NaCl(s)+5H₂O(l) (Ln=Pr, Gd), at T=298.15 K, were determined to be (39.26±0.10) and (5.33±0.12) kJ mol^–1 , respectively. Standard enthalpies of formation of the two complexes at T=298.15 K, Δ_fH^Θ_m {[Ln(Ala)₂(Im)(H₂O)](ClO₄)₃(s)} (Ln=Pr, Gd), were calculated as –(2424.2±3.3) and –(2443.4±3.3) kJ mol^–1 , respectively.     

Standard molar enthalpies of formation of [RE(Gly)<Subscript>4</Subscript>(Im)(H<Subscript>2</Subscript>O)](ClO<Subscript>4</Subscript>)<Subscript>3</Subscript> (<Emphasis Type="Italic">RE</Emphasis>=Eu,Sm)

The two complexes, [RE(Gly)₄(Im)(H₂O)](ClO₄)₃(s)(RE = Eu, Sm), have been synthesized and characterized. The standard molar enthalpies of reaction for the following reactions, RECl₃·6H₂O(s)+4Gly(s)+Im(s)+3NaClO₄(s) = =[RE(Gly)₄(Im)(H₂O)](ClO₄)₃(s)+3NaCl(s)+5H₂O(l), were determined by solution-reaction colorimetry. The standard molar enthalpies of formation of the two complexes at T = 298.15 K were derived as Δ_f H _m^Θ {Eu(Gly)₄(Im)(H₂O)}(ClO₄)₃(s)} = = −(3396.6±2.3) kJ mol⁻¹ and Δ_f H _m^Θ {Sm(Gly)₄(Im)(H₂O)}(ClO₄)₃(s)} = −(3472.7±2.3) kJ mol⁻¹, respectively.     

镧与L-酪氨酸和甘氨酸三元固态配合物的热化学研究

由于稀土元素镧与氨基酸形成的配合物具有抗癌、抗肿瘤活性 ,人们对稀土氨基酸配合物的研究产生了浓厚兴趣。有关这类配合物的制备和表征的研究较多[1～ 4] ,而对其热化学性质的研究较少。我们按文献[5] 方法合成了配合物Ｌａ(Ｔｙｒ)(Ｇｌｙ) 3Ｃｌ3·3Ｈ2 Ｏ(ｓ) ,在自行研制的具有恒定温度环境反应热量计上 ,分别测定了Ｌａ2 Ｏ3(ｓ)、氨基酸 [Ｌ 酪氨酸 (Ｌｙｒ) +甘氨酸 (Ｇｌｙ) ]和配合物在2ｍｏｌ·Ｌ- 1 ＨＣｌ溶液中的溶解焓 ,通过设计的热化学循环得出配合反应焓 ,进而计算出Ｌａ(Ｔｙｒ)(Ｇｌｙ) 3Ｃｌ3·3Ｈ2 Ｏ(ｓ)的标准摩尔…     

聚（丙烯酸—丙烯酰胺）—碱金属盐复合物的合成与表征

作为功能材料的一个新品种,高分子固体电解质有极其广泛的应用前景[1]。近年来人们致力于对体系的改性研究[2-5],以提高电解质的室温离子电导率和获得适合的力学性能。本研究用水溶液聚合工艺,以过硫酸盐为引发剂,以丙烯酸为主单体、丙烯酰胺为第二单体,加入适当的增塑剂...     

Combined study of thermochemical properties of nitroform and its salts

A combined method for determination of the standard enthalpies of formation of nitroform and its salts was proposed. The enthalpies of dissolution of nitroform and its ammonium, hydrazinium, guanidinium, and potassium salts in water were measured. The enthalpy of combustion of hydrazinium salt of nitroform was determined by a combustion calorimetry, and its standard enthalpy of formation was calculated. The enthalpy of formation of trinitromethyl anion in indefinitely diluted aqueous solution −24.94±0.79 kJ mol⁻¹, was calculated on the basic of the data obtained for enthalpies of formation and dissolution of ammonium and hydrazinium salts of nitroform. Standard enthalpies of formation of nitroform and its salts were calculated. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2451–2454, December, 1998.     

Enthalpie de formation de la whitlockite Ca18Mg2H2(PO4)14

Pure and well crystallised whitlockite Ca₁₈Mg₂H₂(PO₄)₁₄ has been synthesized by precipitation from the magnesium and calcium nitrates and the diammonic phosphate. The product of the reaction has been characterized by X-ray diffraction, IR spectroscopy and chemical analysis. Using differential conduction calorimeters the enthalpies of solution of the whitlockite and of a mixture of the solid reactants - the tricalcium, the trimagnesium and the dicalcium phosphates - have been measured at 25°C for various concentrations of solid in a 46 wt% nitric acid solution. A combination of the enthalpies of solution with the enthalpies of formation of the reactants allows us to determine the standard enthalpy of formation of the whitlockite. The value deduced, -27,93·10³kJ mol^-1, is compared to the standard enthalpies of formation of the trimagnesium and the tricalcium phosphates. This revised version was published online in August 2006 with corrections to the Cover Date.