Die Kristallstruktur des Calciumazid-Dihydrates

Single crystals of Ca(N₃)₂·2 H₂O have been prepared from aqueous solutions at room temperature. The crystals are monoclinic,a=1 159.0 (3),b=614.2 (2),c=785.5 (2) pm, =106.52 (2)°,Z=4, space group P2₁/n. The crystal structure was determined by single crystal X-ray diffraction (1 109 Mo-K-reflexions,R=0.052). Calcium atoms are surrounded by four azide groups and four water molecules. The coordination polyhedra are antiprism which are sharing azide groups and water molecules to form layers. The lattice constants and powder pattern agree well with values reported earlier for Ca(N₃)₂ · 1.5 H₂O [1]. It was also shown, that Sr(N₃)₂ · 2 H₂O is isotypic with Ca(N₃)₂ · 2 H₂O.

     

Investigation on Vibrational Spectra and Structures of 4-Mercaptopyridine Monomer and Its Dihydrate

Introduction4-Mercaptopyridine(4MPY)has been always em-ployed as a model molecule and a probe molecule forRaman spectra in many studies because of its specialstructure with two active groups and its excellent signalin a Raman spectrum.Therefore,4MPY has b…     

Einkristalluntersuchungen an AgF2

Single Crystal Investigation on AgF₂ For the first time single crystals of AgF₂ (black, metalic bright) have been obtained by heating AgF₂ powder under a mixture of HF and F₂ in autoclaves at 400°C. It crystallizes orthorhombic in the space group Pbca – D (Nr. 61) – with a = 556.8(1), b = 583.1(1) and c = 510.1(1) pm; Z = 4. The Madelung Part of Lattice Energy, MAPLE, and the Effective Coordination Number, ECoN, via the Mean Fictive Ionic Radii, MEFIR, are calculated and discussed.     

Zur Reaktion des Rhenium(VII)-oxids mit 1,4-Dioxan – Kristallstruktur von Re2O7(OH2)2 · 2(1,4-Dioxan)

Reaction of Rhenium(VII) Oxide with 1,4-Dioxane – Crystal Structure of Re₂O₇(OH₂)₂ · 2(1,4-Dioxane) By solvolysis of polymeric Re₂O₇ with 1,4-dioxane in the presence of small amounts of H₂O two products of compositions Re₂O₆(OH)₂ · 3(1,4-dioxane) ( 1 ) and Re₂O₇ · 2H₂O · 2(1,4-dioxane) ( 2 ) are formed. From a complete X-ray single-crystal structure analysis 2 could now be characterized structurally (monoclinic, space group P2₁/c, a = 6.828(3) Å, b = 9.530(2) Å, c = 26.421(8) Å, β = 91.71(3)°, Z = 4). The compound is important as a convenient precursor for the preparation of pure rhenium trioxide. It is to be formulated as Re₂O₇(OH₂)₂ · 2(1,4-dioxane) and contains, contrary to 1 , no 1,4-dioxane coordinated to Re. The crystalline phase consists of a supramolecular arrangement of Re₂O₇(OH₂)₂ units as in “solid perrhenic acid” and of 1,4-dioxane molecules associated through O? H …? O hydrogen bridges. Analogous to dirhenium heptoxide and to solid perrhenic acid one of the rhenium atoms is in tetrahedral, the other is in distorted octahedral coordination.     

Silica Sulfuric Acid/Sodium Dichromate Dihydrate as an Efficient Heterogeneous Method for the Oxidation of Alcohols Under Mild Conditions

A combination of silica sulfuric acid and sodium dichromate dihydrate in the presence of wet SiO 2 were used as an effective oxidizing agent for the oxidation of alcohols to their corresponding aldehyde or ketone derivatives in dichloromethane or toluene with excellent yields.     

原子吸收光谱法测定硫酸盐型卤水中钙

加入BaCl2消除SO_4~(2-)的干扰,原子吸收光谱法测定硫酸盐型卤水中的钙。方法检出限为4.8mg/L(稀释100倍样品)。回收率为96%—98%。RSD(n=12)=1.6%,方法操作简单、灵敏度高、实用性强。