Chemistry of the Ca–Se(IV)–H2O and Ca–Se(VI)–H2O systems at 25 °C

The Ca–Se(IV)–H₂O and Ca–Se(VI)–H₂O systems were studied by contacting either selenious acid or selenic acid solution with calcium oxide to attain equilibrium at 25 °C for one month. Analysis of the final solid phases and the associated solution, together with X-ray diffraction analysis and a study into the graphed relationships, showed the existence of three calcium selenites in the Ca–Se(IV)–H₂O system — Ca₂SeO₃(OH)₂·2H₂O (Se(IV) = 4.8 × 10^− 5–2.8 × 10^− 4 M); CaSeO₃·H₂O (Se(IV) = 2.8 × 10^− 4–0.86 M) and Ca(HSeO₃)₂·H₂O (Se(IV) > 0.86 M). It also showed four calcium selenates in the Ca–Se(VI)–H₂O system — Ca₂SeO₄(OH)₂ (Se(VI) = 0.21–0.39 M); CaSeO₄·2H₂O (Se(VI) = 0.40–9.1 M); CaSeO₄ (Se(VI) = 10.2 M) and CaSe₂O₇ (Se(VI) > 10.8 M). The X-ray diffraction analyses reported and SEM analyses indicate a high degree of crystallinity of all seven compounds. The stability and solubility regions for these compounds were defined versus pH, and the conventional solubility constants and conditional free energies of formation for the less soluble CaSeO₃·H₂O, Ca₂SeO₃(OH)₂·2H₂O, CaSeO₄·2H₂O and Ca₂SeO₄(OH)₂ were calculated from solubility data obtained.     

Syntheses, characterization, and luminescence of two lanthanide complexes [Ln2(acetate)6(H2O)4]·4H2O (Ln=Tb(1), Sm(2))

Two dinuclear compounds [Ln2(acetate)6(H2O)4]·4H2O (Ln=Tb(1), Sm(2)) were obtained by the hydrothermal reaction of Ln2O3 with malonic acid at 150 ℃. Both compounds were characterized by elemental analyses, infrared spectra, and single crystal X-ray diffraction. The results showed that complexes 1 and 2 were isomorphous and crystallize in triclinic space group P(-1). The coordination geometry around Ln(III) ions in the complexes 1 and 2 was a distorted tricapped trigonal prism with a nine coordination. In the crystal, the molecular organization was further stabilized by well-defined weak hydrogen bonding interactions between the neutral dinuclear molecular units that led to the formation of a three-dimensional network. The fluorescence properties of the two complexes 1 and 2 in organic solvents were also studied. The results show that the ligand acetate favored energy transfer to the emitting energy level of Tb(III) in complex 1. Some factors that influence the fluorescent intensity were also discussed in the article.     

Effects of Cerium Oxide on Ni／Al2O3 Catalysts for Decomposition of CH4 and C2H4

Characteristics of carbon deposition of CH4 and C2H4 decomposition over supported Ni and Ni-Ce catalysts were studied by using a pulse reaction as well as BET, TPR, XPS and hydrogen chemisorption techniques. It is found that there is a metal-semiconductor interaction (MScI) in the Ni-Ce catalyst, and the effect of MScI on the carbon deposition of CH4 decomposition is opposite to that of C2H4. A novel model of carbon deposition of CH4 or C2H4 decomposition was proposed.     

Synthesis and Structural Characterization of Adduct [La(NO_3)_3·4H_2O]·2(BQEB)

Ｂｅｃａｕｓｅｏｆｔｈｅｉｒｐｏｓｓｉｂｌｅｒｅｌｅｖａｎｃｅｔｏｍｏｄｅｌｃｏｍｐｏｕｎｄｓｏｆｃａｔｉｏｎｔｒａｎｓｐｏｒｔａｃｒｏｓｓｍｅｍｂｒａｎｅｓ,ｄｉｆｆｅｒｅｎｔｔｙｐｅｓｏｆｏｐｅｎｃｈａｉｎ“ｃｒｏｗｎ”ｅｔｈｅｒｍｏｌｅｃｕｌｅｓｈａｖｅｂｅｅｎｓｙｎｔｈｅｓｉｚｅｄｉｎｏｒｄｅｒｔｏｓｔｕｄｙｔｈｅｉｒｉｎｔｅｒａｃｔｉｏｎｗｉｔｈｓｏｄｉｕｍ ,ｐｏｔａｓｓｉｕｍａｎｄｒａｒｅｅａｒｔｈｉｏｎｓ[1,2 ] .Ｐａｎｅｔａｌ.[3 ] ｓｈｏｗｅｄｔｈａｔＣｅ3 ｆｏｒｍｓａ 1∶1ｃｏｍ…     

稀土配合物[REL3(4-picNO)H2O]的合成与表征

合成了2,3-二氯异丁酸根和4-甲基吡啶氮氧化物稀土三元配合物(RE=La、Ce、Pr、Nd、Sm、Eu).通过元素分析、红外、紫外、荧光、X射线粉末衍射、XPS、热分析以及摩尔电导等分析手段,确定了配合物的组成为[REL3(4-picNO)H2O](L= CH3C2H2Cl2COO -),并对它们的性质进行了讨论.     

Thermodynamics and Structure of CaO-Al2O3-3 Mass Pct B2O3 Slag at 1773 K (1500 °C)

Metallurgical and Materials Transactions B - Activity values of Al2O3 in CaO-Al2O3-B2O3 systems at 1773 K (1500 °C) were determined experimentally using a...     

新型间硝基苯甲酸稀土配位聚合物[Nd2(C7H4O4N)7(H2O)4]n的水热合成和晶体结构

采用水热方法合成出一种新型的间硝基苯甲酸稀土配位聚合物[Nd2(C7H4O4N)7H2O]n,并通过元素分析、红外光谱、X射线单晶结构分析对该配位聚合物进行了表征.标题配位聚合物的晶体属于三斜晶系,P1空间群,晶胞参数a=0.9848(2)nn,b=1.131 4(2)nm,c=1.366 3(3)nm,α=69.22(3).,β=82.48(3).,γ=82.21(3).,V=1.4045(5)nm3,Dc=1.806g/cm3,Z=1.结构分析表明:标题化合物是由稀土金属Nd(Ⅲ)和间硝基苯甲酸组成的配位聚合物,此聚合物通过Ln-O-C-O-Ln形成无限一维链状结构,进一步又通过分子间氢键连接形成复杂的三维氢键网络结构.     

新型电荷转移配合物(C9H8N)10(NH4)3[Y(SiMo11O39)2]·20H2O的合成与表征

由三元杂多化合物 (NH4) 1 3 [Y(Si Mo1 1 O3 9) 2 ]· 36 H2 O与喹啉反应合成了电荷转移化合物 (C9H8N) 1 0(NH4) 3 [Y(Si Mo1 1 O3 9) 2 ]· 2 0 H2 O。采用元素分析、X射线粉末衍射、红外光谱、固体漫反射电子光谱进行了表征。结果表明 :喹啉通过 N原子结合质子形成阳离子与稀土杂多阴离子成盐 ,固体化合物中阴离子和阳离子之间存在较强的相互作用 ;化合物在光激发下发生分子内电荷转移 ,导致有机 C9H8N 大阳离子的氧化和稀土杂多阴离子的还原 ,标题化合物颜色由黄转变为深蓝色     

[Nd(PW11O39)(H2O)3](H2bpy)2·4H2O的水热合成及晶体结构

采用水热法合成稀土无机有机杂化化合物[Nd(PW11O39)(H2O)3 ](H2bpy)2·4H2O.采用NdCl3·6H2O,(NH4)3PW12O40·3H2O, 4,4'-联吡啶(bpy),和去离子水(摩尔比为4∶1∶4∶3900, pH=6)在130℃下进行水热反应3天,得到标题化合物的紫红色块状晶体,并进行了红外光谱分析,元素分析.用单晶X射线衍射法测得晶体结构,属三斜晶系,空间群为P-1,晶胞参数为a=1.18824(9) nm,b =1.35707(10)nm,c=1.77691(13)nm,α=71.551(2)°,β=82.478(2)°,γ=80.568(2)°.该晶体由无机的共价链∞1[Nd(PW11O39)(H2O)3]4- 和有机的二质子化的4,4'-联吡啶(H2bpy)2 及结晶水分子堆积而成的, 是一个新的稀土磷钨酸盐无机有机杂化化合物.     

Thermodynamic activity of Na2O in Na2O-CaO-SiO2, Na2O-MgO-SiO2, and Na2O-CaO-SiO2-Al2O3 melts at 1400°C

A gas phase equilibration technique was used to generate Na₂O isoactivity data at high-silica compositions in the systems Na₂O-CaO-SiO₂, Na₂O-MgO-SiO₂, and Na₂O-CaO-SiO₂-(10 and 20 wt pct) A1₂O₃ at 1400 °. Loga _{Na 2 O} values referenced to pure liquid Na₂O at 1400 ° as standard state ranged from about ?8.0 to ?7.0. Silica activities were calculated in the Na₂O-CaO-SiO₂ system using the Gibbs-Duhem equation. Richardson’s model for ideal mixing of basic oxides in silica was applied to the Na₂O-CaO-SiO₂ system. The model shows best fit when cationic mixing is assumed to occur on divalent sites. The alkali retention in slags has been described using a defined “sodium capacity”. The temperature variation of alkali retention was estimated, and the resulting sodium capacity was used to evaluate alkali stability in blast furnace slags.     

Interactions in the Al2O3 ― ZrO2 ― La2O3 System at 1250 and 1650°C

Triangulation has been determined for the Al₂O₃ ZrO₂ La₂O₃ system, and 1250 and 1650°C isothermal sections of the phase diagram have been constructed. The LaAlO₃ La₂Zr₂O₇ section is quasibinary, while the LaAlO₃ T-ZrO₂ and La₂O₃ ·11Al₂O₃ T-ZrO₂ ones are partially quasibinary. The triangulation of the ternary system is based on ZrO₂ and a phase containing it. No ternary compounds or regions of ternary solid solutions have been identified.     

Distribution of Calcium and Aluminum Between Molten Silicon and Silica-Rich CaO-Al2O3-SiO2 Slags at 1823 K (1550 °C)

Metallurgical and Materials Transactions B - Oxidative refining of silicon after tapping from the furnace is performed to remove calcium and aluminum impurities. Depending on the slag composition,...     

Evolution and coarsening of Al2O3 dispersoids at 500 °C to 600 °C in a mechanically alloyed Al-Ti-O based material

The formation and coarsening of Al₂O₃ dispersoids have been investigated at 500 °C, 550 °C, and 600 °C in a mechanically alloyed (MA) extrusion of composition Al-0.35wt pct Li-1wt pct Mg-0.25wt pct C-10vol pct TiO₂ for times up to 1500 hours. In the as-extruded condition, the dispersed phases included Al₃Ti, Al₄C₃, MgO, cubic TiO (C-TiO), monoclinic TiO (M-TiO), TiO₂, and a small amount of Al₂O₃. However, numerous Al₂O₃ dispersoids (various polymorphs: η, γ, α, and δ) with “block-shaped” morphology were formed after heat treatment due to reduction of C-TiO, M-TiO, and TiO₂. Transmission electron microscopy (TEM) and X-ray diffraction (XRD) showed conclusively the transformation of these phases to additional Al₂O₃ and Al₃Ti. High resolution TEM showed that the α-Al₂O₃ dispersoids exhibited some lattice matching with the α-Al matrix. Coalescence of the block-shaped Al₂O₃ dispersoids occurred after heat treatment, and Al₄C₃ also became attached to them. The length and width of the block-shaped Al₂O₃ dispersoids increased by a factor of ∼1.55 between 340 and 1500 hours at 600 °C.     

Effect of P,B4C,and (Ti,Cr)C Additives on the Kinetics of High-Temperature Oxidation of Chromium Carbide Alloys at 1000°C

We have used the thermogravimetric method to study the effect of B₄C, (Ti, Cr)C, and phosphorus additives on the kinetics of oxidation of chromium carbide alloys of the type 85% Cr₃C₂ 15% Ni (KKhN15) and 85% Cr₃C₂ 15% (Ni P) (KKhNF15), in air under isothermal heating conditions at 1000°C from 0 to 5 h. We have established that the alloys are characterized by insignificant increase in mass in the initial oxidation period (3 h), after which the degree of oxidation increases somewhat. The nature of the oxidation kinetics for KKhNF15 alloys, containing 0.016-0.64% B₄C, varies from some mass increase in the initial period (20 min) to later mass loss in connection with formation of CO, CO₂ and rapid evaporation of boron anhydride B₂O₃. The maximum resistance to oxidation is exhibited by alloys of the type KKhN15 and KKhNF15, the mass increase of which is 0.128-0.256 mg/cm² after 5 h of heating at 1000°C.     

Synthesis and Crystal Structure of [Yb(NTO)_3(H_2O)_4]·6H_2O

ＳｙｎｔｈｅｓｉｓａｎｄＣｒｙｓｔａｌＳｔｒｕｃｔｕｒｅｏｆ［Ｙｂ（ＮＴＯ）３（Ｈ２Ｏ）４］·６Ｈ２ＯＳｏｎｇＪｉｒｏｎｇ（宋纪蓉），ＤｏｎｇＷｕ（董武）（ＤｅｐａｒｔｍｅｎｔｏｆＣｈｅｍｉｃａｌＥｎｇｉｎｅｒｉｎｇ，ＮｏｒｔｈｗｅｓｔＵｎｉｖｅｒ...     

NaGa(C7H3NO4)2·2H2O光催化剂的制备与性能

2,6-吡啶二甲酸钠与三氯化镓在pH≈3的条件下直接反应,合成了NaGa(C7H3NO4)2·2H2O配合物单晶.通过元素分析、红外及X射线衍射分析确定了配合物的结构.以该配合物作为催化剂,用罗丹明B模拟染料废水进行了光催化降解脱色试验,对影响反应的各种条件(如催化剂的投加量,染料的初始浓度,通氧速率及光源)进行了考察.结果表明,在催化剂为20mg,染料初始浓度为2.0×10-4mol·L-1,通氧速率为200ml·min-1,光源为500W汞灯时,配合物NaGa(C7H3NO4)2·2H2O具有优良的催化活性,1h内对罗丹明B的降解率可达98.9%.     

Synthesis and Structure of Polynuclear Complex [La(bphsb)2(NO3)3]n

Ｓｏｍｅｌａｎｔｈａｎｉｄｅｃｏｍｐｌｅｘｅｓｗｉｔｈｄｉｓｕｌｆｏｘｉｄｅｓｈａｖｅｂｅｅｎｓｔｕｄｉｅｄ［１，２］．Ｈｏｗｅｖｅｒ，ｒｅｌａｔｉｖｅｌｙｌｉｔｌｅｗｏｒｋｈａｓｂｅｅｎｄｏｎｅｏｎｃｒｙｓｔａｌｓｔｒｕｃｔｕｒｅｏｆｔｈｅｓｅｃｏ...     

Synthesis and Crystal Structure of a 4f-3d Complex [La(DMF)_6(H_2O)_3][Cr(CN)_6]·2H_2O

Ｒｅｃｅｎｔｌｙ ,ｔｈｅｒｅｈａｓｂｅｅｎｃｏｎｓｉｄｅｒａｂｌｅｉｎ ｔｅｒｅｓｔｉｎｌａｎｔｈａｎｉｄｅ(Ⅲ )ｈｅｘａｃｙａｎｏｆｅｒｒａｔｅｓａｎｄｔｈｅａｎａｌｏｇｏｕｓｃｏｂａｌｔ(Ⅲ )ａｓｗｅｌｌａｓｃｈｒｏｍｉｕｍ(Ⅲ )ｃｏｍｐｌｅｘｅｓｂｅｃａｕｓｅｏｆｔｈｅｉｒｐｏｔｅｎｔｉａｌａｓｃａｔａｌｙｔｉｃ ,ｓｅｍｉｃｏｎｄｕｃｔｉｖｅ ,ａｎｄｍａｇｎｅｔｉｃｍａｔｅ ｒｉａｌｓ[1～ 4] .Ｆｏｒｅｘａｍｐｌｅ ,ｍａｇｎｅｔｉｃｓｔｕｄｉｅｓｏｎａｓｅｒｉｅｓｏｆｔｈｒｅｅ ｄｉｍｅｎｓｉｏ…