Sr2(OLi2Sr4)[CrN4]2, ein Nitridochromat(VI)‐Oxid mit Sauerstoff in tetragonal‐bipyramidaler Koordination durch Lithium und Strontium

Sr₂(OLi₂Sr₄)[CrN₄]₂, a Nitridochromate(VI)‐Oxide with Oxygen in Tetragonal‐Bipyramidal Coordination by Lithium and Strontium Green gleaming crystals of Sr₂(OLi₂Sr₄)[CrN₄]₂ were prepared by reaction of Li, Sr and CrN/Cr₂N (approximate 1 : 1 mixture) with flowing nitrogen at 900 °C (molar overall composition Li : Sr : Cr = 6 : 1 : ∼3). The oxygen content results from a leak in the gas supply. The crystal structure was determined by single crystal methods (triclinic; P1; a = 615.87(9) pm, b = 682.50(10) pm, c = 754.30(8) pm, α = 82.302(14)°, β = 75.197(10)°, γ = 70.133(13)°; Z = 1) and contains distorted tetragonal bipyramids (OLi₂Sr₄)⁸⁺ and [Cr^VIN₄]^6–‐tetrahedra besides Sr²⁺.     

The determination and application of 87Sr/86Sr ratio in verifying geographical origin of wheat

As ⁸⁷Sr/⁸⁶Sr ratio plays a significant role in authenticating the geographical origin of foodstuff, it is important to identify where the ⁸⁷Sr/⁸⁶Sr signature in food comes from, and the methods of ⁸⁷Sr/⁸⁶Sr ratio analysis in food and environmental samples. Wheat with three genotypes, soil and groundwater samples were collected from three regions of China during harvest time of 2014. The ⁸⁷Sr/⁸⁶Sr ratios in the samples were determined by thermal ionization mass spectrometer in order to investigate the possible source of ⁸⁷Sr/⁸⁶Sr in wheat, and the concentrations of Rb and Sr in wheat and soils were also detected by inductively coupled plasma mass spectrometry and combined with ⁸⁷Sr/⁸⁶Sr ratio in order to trace the geographical origin of wheat. The ⁸⁷Sr/⁸⁶Sr ratio, the contents Rb and Sr, and Rb/Sr ratio of wheat and soil samples showed significant differences among three regions. The ⁸⁷Sr/⁸⁶Sr ratios and the concentrations of Rb and Sr in soils were higher than those in corresponding wheat. The ⁸⁷Sr/⁸⁶Sr ratio in wheat was identical to that corresponding soil NH₄NO₃ extracts (labile fraction of soil) and groundwater. Wheat uptake more Rb than Sr. 3D distribution of ⁸⁷Sr/⁸⁶Sr, Rb and Sr could identify wheat samples from different regions clearly. The ⁸⁷Sr/⁸⁶Sr ratio of wheat reflects the ⁸⁷Sr/⁸⁶Sr ratio of the associated environment including soil and groundwater. It is expected that the use the parameters of ⁸⁷Sr/⁸⁶Sr ratio, the contents of Rb and Sr will allow to trace geographical origin of wheat. Copyright © 2017 John Wiley & Sons, Ltd.     

Separation of Cs and Sr using polyoxonium compounds

Extraction separation and concentration of Cs and Sr from aqueous solutions, containing macroconcentrations of competitive ions (Li⁺, Na⁺, K⁺, Mg²⁺, Ca²⁺, Al³⁺, Fe³⁺) by the nitrobenzene solutions of bis-1,2-dicarbollylcobaltate in the presence of linear and cyclic polyoxonium compounds (POC) has been investigated. It has been found, that the addition of DB18C6 increases the distribution ratio of cesium (D_cs) but the addition of other crowns and PEG decreases D_Cs value and selectivity of D_Sr and the selectivity of Sr/Ca separation. Separation factors of Sr/Ca increase from (Sr/Ca)2 (found in the absence of POD) to (Sr/Ca)50 (for DB18C6), (Sr/Ca)100 (for 18C6 and DCH18C6) and (Sr/Ca)1000 for 15C5.     

Sr(NO3)2·DCH18C6配合物晶体结构与辐射稳定性

二环己基-18-冠-6（DCH18C6）可以有效地从高放废液中分离⁹⁰Sr,对于减小放射性废物的危害和实现高放废物的减容有重要意义. 由于在实际应用中DCH18C6处于射线照射下,其结构可能会被破坏并引起络合能力的变化,因此有必要对该配合物的辐射稳定性进行研究. 本文合成了Sr（NO₃）₂·DCH18C6 配合物晶体,并通过单晶X射线衍射（XRD）与扩展X射线吸收精细结构谱（EXAFS）等方法进行了表征,确定Sr²⁺与周围氧原子的配位数为10,Sr―O平均键长约为0.268 nm/0.266 nm（XRD/EXAFS）. 配位原子来自DCH18C6 的六个氧原子以及两个作为双齿配体的硝酸根的四个氧原子. 对该配合物晶体在空气中进行γ辐照,EXAFS结果表明吸收剂量为400 kGy时,Sr―O键长及配位数没有发生变化,配位结构没有被破坏,具有很好的耐辐照稳定性. 显微红外光谱（Micro-FTIR）结果进一步证明辐照后冠醚环的部分C―H 键氧化为羟基或羰基,但并不影响DCH18C6与Sr²⁺的配位结构.     

A Thermodynamic Study Between 18-Crown-6 with Mg2+, Ca2+, Sr2+and Ba2+ Cations in Water–Methanol and Water–Ethanol Binary Mixtures Using The Conductometric Method

The complexation reactions between Mg²⁺, Ca²⁺, Sr²⁺ and Ba²⁺ cations with the macrocyclic ligand, 18-Crown-6 (l8C6) in water–methanol (MeOH) binary systems as well as the complexation reactions between Ca²⁺ and Sr²⁺ cations with 18C6 in water–ethanol (EtOH) binary mixtures have been studied at different temperatures using conductometric method. The conductance data show that the stoichiometry of all the complexes is 1:1. It was found that the stability of 18C6 complexes with Mg²⁺, Ca²⁺, Sr²⁺ and Ba²⁺ cations is sensitive to solvent composition and in all cases, a non-linear behaviour was observed for the variation of log K _f of the complexes versus the composition of the mixed solvents. In some cases, the stability order is changed with changing the composition of the mixed solvents. The selectivity order of 18C6 for the metal cations in pure methanol is: Ba²⁺ > Sr²⁺ > Ca²⁺ > Mg²⁺. The values of thermodynamic parameters (Δ H _c ° and Δ S _c °) for formation of 18C6–Mg²⁺, 18C6–Ca²⁺, 18C6–Sr²⁺ and 18C6–Ba²⁺complexes were obtained from temperature dependence of the stability constants. The obtained results show that the values of (Δ H _c ° and Δ S _c °) for formation of these complexes are quite sensitive to the nature and composition of the mixed solvent, but they do not vary monotonically with the solvent composition.This revised version was published online in July 2005 with a corrected issue number.     

Distribution of Strontium in the System Water — Ca(NO3)2 — Nitrobenzene — Strontium Dicarbollylcobaltate — 18-crown-6

From several strontium distribution experiments with ⁸⁵Sr tracer, the extraction constant corresponding to the equilibrium Ca²⁺(aq)+SrL²⁺(nb) CaL²⁺(nb)+Sr²⁺ (aq) in the two-phase water-nitrobenzene system (L = 18-crown-6; aq = aqueous phase, nb = nitrobenzene phase) was tentatively evaluated as log K _ex (Ca²⁺,SrL²⁺) = –1.9±0.1. Furthermore, the stability constant of the calcium — 18-crown-6 complex in nitrobenzene saturated with water was calculated for a temperature of 25 °C: log _nb(Cal²⁺) = 10.1±0.1.     

Die Kristallstrukturen der Polytelluride [Ca(DMF)6]Te4, [Sr(15-Krone-5)2]Te4 · H2O, {[BaCl(18-Krone-6)(DMF)2]2[BaCl(18-Krone-6)(DMF) (H2O)]2(Te4)2} und [Ph3PNPPh3]2Te5 · 2 DMF

Crystal Structures of the Polytellurides [Ca(DMF)₆]Te₄, [Sr(15-Crown-5)₂]Te₄ · H₂O, {[BaCl(18-Crown-6)(DMF)₂]₂[BaCl(18-Crown-6)(DMF) (H₂O)]₂(Te₄)₂}, and [Ph₃PNPPh₃]₂Te₅ · 2 DMF The title compounds were formed by alkalimetal polytelluride solutions in dimethylformamide (DMF) in the presence of the corresponding counter ions as well as in the presence of 15-crown-5 or 18-crown-6. Single crystals were obtained upon using additional diethylether. [Ca(DMF)₆]Te₄: Space group C2/c, Z = 4, 1024 observed unique reflections, R = 0.055. Lattice dimensions at ?70°C: a = 1776.1; b = 813.0 c = 2545.9pm; β = 102.90°. The compound consists of centrosymmetric [Ca(DMF)⁶]²⁺ ions, in which the calcium ions are octahedrally coordinated by the six oxygen atoms of the DMF molecules, and chain-like Te [Sr)15-crown-5)₂]Te₄ · H₂O: Space group C2/c, Z = 4, 3322 observed unique reflections, R = 0.058. Lattice dimensions at ?70°C: a = 1450.5; b = 1407.3; c = 1660.9 pm; β = 110.22°. The compounds forms centrosymmetric cations [Sr(15-crown-5) ₂]²⁺, in which the Sr²⁺ ion is sandwich-like surrounded by the ten oxygen atoms of the crown ether molecules, and chain-like Te₄^2? ions, which are associated in the lattice forming polymeric chains. {[BaCl(18-crown-6)(DMF) ₂]₂[BaCl(18-crown-6)(DMF)· (H₂O)] ₂(Te₄)₂}: Space group P1 , Z = 1, 3189 observed unique reflections, R = 0.054. Lattice dimensions at 19°C: a = 986.1; b = 1052.8; c = 2696.4 pm; α = 89.34°; β = 88.68°; γ = 89.56°. The compound consists of chain-like Te ions without symmetry and of the two somewhat different cations [BaCl(18-crown-6)(DMF) ₂]₂²⁺, in which the Ba²⁺ ions dimerize via centroysmmetric rings. Along with the six oxygen atoms of the crown ether molecules and the oxygen atoms of the DMF molecules, the oxygen atoms of the DMF and water molecule, respectively, the Ba⁺ ions achieve coordination number ten. [Ph₃PNPPh₃]₂Te₅ · 2DMF: Space group Pc, Z = 2, 5971 observed unique reflections, R = 0.058. Lattice dimensions at 20°C: a = 20°C: a = 1085.2; b = 1287.0; c = 2715.9 pm; β = 90.19°. The compounds consists of [Ph₃PNPPh₃]₊ ions, chain-like Te₅^2? ions, and incorporate DME molecules without bonding interaction. The ₅^2? ions are associate via polymeric chains in which left- and right handed individuals are alternating.     

Extraction of85Sr by the nitrobenzene solution of bis-1,2-dicarbollylcobaltate in the presence of dibenzo-18-crown-6

Extraction of strontium by the nitrobenzene solution of bis-1,2-dicarbollylcobaltate in the presence of dibenzo-18-crown-6 (DB18C6, L) has been investigated. the equilibrium data and the typical maxima concerning the dependencies of the Sr distribution ratios on the total analytical concentration of DB18C6 in the system under study can be explained assuming that the particles Sr²⁺, SrL²⁺, SrL₂ ²⁺, SrHL³⁺ and SrHL₂ ³⁺ are extracted into the nitrobenzene phase. The values of the corresponding extraction and stability constants of the extracted species in nitrobenzene saturated with water have been determined.     

High temperature synthesis of some strontium and barium 2,6-dibenzylphenolates

Direct treatment of HOdbp (= 2,6-dibenzylphenol) with strontium or barium metal in the absence of solvent at high temperature provides the corresponding phenolates Sr(Odbp)₂ and Ba(Odbp)₂. Recrystallisation of Ba(Odbp)₂ from THF gave a good yield of the crystalline dimer [Ba(Odbp)₂(THF)]₂ · 2THF. Attempted recrystallisation of Sr(Odbp)₂ from THF mostly yielded microcrystalline material characterized as [Sr(Odbp)₂]_n but on one occasion gave a small crop of crystalline [Sr₉(Odbp)₈(O₂SiMe₂)₄(OH)₂(THF)₆(OH₂)₂] · 6THF derived from the adventitious reaction of Sr(Odbp)₂ with dimethylsilicone grease ({OSiMe₂}_∞). In the solid-state [Ba(Odbp)₂(THF)]₂ · 2THF displays significant intramolecular Ba?π-arene interactions with the pendant benzyl substituents. [Sr₉(Odbp)₈(O₂SiMe₂)₄(OH)₂(THF)₆(OH₂)₂] · 6THF features a square prismatic [Sr(O₂SiMe₂)₄]⁶⁻ core capped by two inverse crown-like square [Sr₄(Odbp)₄(OH)(L)₄]³⁺ units, where L = OH₂ or THF, that are staggered with respect to the cuboidal core.     

M(SCN)2 (M = Eu,Sr, Ba): Kristallstruktur,thermisches Verhalten,Schwingungsspektroskopie

M(SCN)₂ (M = Eu, Sr, Ba): Crystal Structure, Thermal Behaviour, Vibrational Spectroscopy Single crystals of M(SCN)₂ (M = Eu, Sr, Ba) have been obtained via metathesis of NaSCN and MCl₂ (M = Eu, Sr, Ba) at 340 °C. The isotypic crystal structures of the thiocyanates M(SCN)₂ (C2/c, Z = 4, Eu: a = 979.3(2), b = 660.8(1), c = 815.7(2) pm, β = 91.58(3)°, R_all = 0.0245, Sr: a = 985.5(2), b = 662.9(2), c = 819.6(2) pm, β = 91.29(3)°, R_all = 0.0435, Ba: a = 1018.8(2), b = 687.2(1), c = 852.2(1) pm, β = 92.43(2)°, R_all = 0.0392) contain alternating layers of M²⁺ and SCN^–. According to M(SCN)_4/4(NCS)_4/4 M²⁺ is eight‐coordinated by four sulfur and four nitrogen atoms forming a square antiprism. Thermal investigations show that the compounds melt without decomposition. Vibrational spectroscopic investigations are presented and discussed.     

Study of Complex Formation of Dibenzo-18-Crown-6 with Ce3+, Y3+, $\mathrm{UO}_{2}^{2 +}$ and Sr2+ Cations in Acetonitrile–Dioxane Binary Solvent Mixtures

The complexation reactions of dibenzo-18-crown-6 (DB18C6) with Ce³⁺, Y³⁺, UO₂^{2 +}\mathrm{UO}_{2}^{2 +} and Sr²⁺ cations were studied in acetonitrile–dioxane (AN–dioxane) binary solvent solutions at different temperatures by the conductometric method. The stability constants of the resulting 1:1 complexes were determined from computer fitting of the conductance–mole ratio data. The results show that dibenzo-18-crown-6 does not exhibit selectivity for the cation whose ionic size is closest to the cavity size of this macrocyclic ligand in AN–dioxane binary solvent solutions. A nonlinear relationship was observed between the stability constants (log ₁₀ K _f) of these complexes with the composition of the AN–dioxane binary solvent. Values of thermodynamic parameters (DH_c^°, DS_c^°\Delta H_{\mathrm{c}}^{\circ}, \Delta S_{\mathrm{c}}^{\circ}) for complexation reactions were obtained from the temperature dependence of the stability constants. The results show that the values along with the sign of these parameters are influenced by the nature and composition of the mixed solvent.     

Ruthenium-Based Perovskitelike Phases: Synthesis, Structure, and Properties

This paper reports on synthesis and X-ray diffraction study of two groups of phases obtained from batch mixtures: (La,Sr _k+1(Ru,Cu) _k O_3k+1 and (La,Sr)₃(Ru,Cu)₃O₆₊ (group I); RuSr₂LnCu₂O_8– (Ln = Nd for the first time, Sm, Eu, Gd, (Gd,Y) for the first time), RuSr₂(Ln,Ce⁴⁺)₂Cu₂O_10– (Ln = Pr and Nd for the first time, Sm, Eu, Gd, (Gd,Y) for the first time), and (Ru,Cu)Sr₂(Ln,Ce⁴⁺)₂Cu₂O_10– (Ln = Tb and Y for the first time) (group II). In group I, phases with K₂NiF₄, Sr₃Ti₂O₇, and cubic perovskite type structures are typically formed; in group II, these are respectively (Ru,Cu)(Sr,Ln)₂(Ln,Sr)Cu₂O_8– (1212 type), (Ru,Cu)(Sr,Ln)₂(Ln,Ce⁴⁺)₂Cu₂O_10– (1222 type), and cubic perovskite type structures (the content of the latter depends on the type of Ln). Variation of the formal charge (f.c.) of Ru (group I) and Cu (group II) was evaluated in relation to the cation composition of the phases (groups I and II) and the content of superstoichiometric oxygen (group II). Phases of 1222 type with Ln = Nd, Sm, Eu, Gd, and (Gd,Y) and phases of 1212 type with Ln = Gd exhibited superconducting properties with T _{c max} 40 K.     

Evaluation of strontium isotope abundance ratios in combination with multi-elemental analysis as a possible tool to study the geographical origin of ciders

In order to evaluate alternative analytical methodologies to study the geographical origin of ciders, both multi-elemental analysis and Sr isotope abundance ratios in combination with multivariate statistical analysis were estimated in 67 samples from England, Switzerland, France and two Spanish regions (Asturias and the Basque Country). A methodology for the precise and accurate determination of the ⁸⁷Sr/⁸⁶Sr isotope abundance ratio in ciders by multicollector inductively coupled plasma mass spectrometry (MC-ICP-MS) was developed. Major elements (Na, K, Ca and Mg) were measured by ICP-AES and minor and trace elements (Li, Be, B, Al, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, As, Se, Rb, Sr, Y, Mo, Cd, Sn, Sb, Cs, Ba, La, Ce, W, Tl, Pb, Bi, Th and U) were measured by ICP-MS using a collision cell instrument operated in multitune mode. An analysis of variance (ANOVA test) indicated that group means for B, Cr, Fe, Ni, Cu, Se, Cd, Cs, Ce, W, Pb, Bi and U did not show any significant differences at the 95% confidence level, so these elements were rejected for further statistical analysis. Another group of elements (Li, Be, Sc, Co, Ga, Y, Sn, Sb, La, Tl, Th) was removed from the data set because concentrations were close to the limits of detection for many samples. Therefore, the remaining elements (Na, Mg, Al, K, Ca, Ti, V, Mn, Zn, As, Rb, Sr, Mo, Ba) together with ⁸⁷Sr/⁸⁶Sr isotope abundance ratio were considered for principal component analysis (PCA) and linear discriminant analysis (LDA). Finally, LDA was able to classify correctly 100% of cider samples coming from different Spanish regions, France, England and Switzerland when considering Na, Mg, Al, K, Ca, Ti, V, Mn, Zn, As, Rb, Sr, Mo, Ba and ⁸⁷Sr/⁸⁶Sr isotope abundance ratio as original variables.     

Sr5Ge2N6 – A Nitridogermanate with Edge‐sharing Double Tetrahedra

The new nitridogermanate Sr₅Ge₂N₆ was obtained as a coarsely crystalline product by Na‐flux technique employing a reaction of Sr, Na, NaN₃ and GeO₂ in weld shut tantalum‐tubes at temperatures up to 760 °C. The crystal structure was determined by single‐crystal X‐ray methods: (Sr₅Ge₂N₆, space group C2/c (no. 15), a = 1040.8(2), b = 652.08(13), c = 1356.5(3) pm, β = 100.29(3)°, V = 905.8(3)·10⁶ pm³, Z = 4, 1240 observed reflections, 61 parameters, R1 = 0.031). In the solid, there are edge‐sharing [Ge₂N₆]¹⁰⁻ double tetrahedra surrounded by Sr²⁺ ions. Sr₅Ge₂N₆ was found to be isotypic with Ca₅Si₂N₆.     

A new type of orthoborates: ASr4La3(BO3)6 (A = Li,Na)

Two new rare earth containing orthoborate crystals ASr₄La₃(BO₃)₆ (A = Li, Na) have been obtained by spontaneous nucleation from high-temperature melts of A₂O–SrO–La₂O₃–B₂O₃–AF. X-ray diffraction analyses show that they both crystallize in the rhombohedral space group R-3 with cell parameters of a = 12.309(7) Å, c = 9.316(7) Å and a = 12.4049(13) Å, c = 9.348(2) Å for the Li and Na compounds respectively. Similar to the large A′₆MM′(BO₃)₆ family, these compounds are all related to the structure of Sr₃Y(BO₃)₃ with La and Sr statistically occupy the Sr site, and the alkaline elements and remaining Sr enter the ordered Y1 and Y2 sites, which can be approximately represented as (La_2.91Sr_3.09)(La_0.09Sr_0.91)Li[B₆O₁₈] and (La_2.85Sr_3.15)(La_0.15Sr_0.85)Na[B₆O₁₈]. The characteristic of the structure is that the La/Sr and isolated BO₃ groups form a network with tunnels along the c-axis where the alkaline A and Sr ions alternatively reside. The optical transmission spectrum shows that the ultraviolet absorption edge of NaSr₄La₃(BO₃)₆ crystal is about 193 nm and Raman spectra reveal that both crystals possess sharp peaks at 930 cm⁻¹.     

Ein Neues gemischtvalentes Oxoosmat(VI,VII): Sr11Os26+Os27+O24

A New Mixed Valenced Oxoosmate(VI, VII): Sr₁₁Os₂⁶⁺Os₂⁷⁺O₂₄ . Single crystals of Sr₁₁Os₂⁶⁺Os₂⁷⁺O₂₄ were prepared in closed silver bombs using SrO, osmium and an extend of KO₂. It crystallizes with monoclinic symmetry, space group C–I12/a1 a = 11.703; b = 16.058; c = 11.696 Å; β = 90.03°; Z = 4. Sr₁₁Os₂⁶⁺Os₂⁷⁺O₂₄ shows a new crystal structure characterized by a [Sr₁₁O₂₄]^26? network and incorporated Os⁶⁺ and Os⁷⁺ ions. Calculations of the coulombterm of lattice energy shows an orderer distribution of the two oxidation states of osmium.     

Ba2(CN2)(CN)2 und Sr2(CN2)(CN)2 – die ersten gemischten Cyanamid-cyanide

Ba₂(CN₂)(CN)₂ and Sr₂(CN₂)(CN)₂ – the First mixed Cyanamide Cyanides The mixed cyanamide-cyanides M₂(CN₂)(CN)₂ (M = Ba, Sr) were synthesized by the reaction of Ba₂N and SrCO₃, respectively, with HCN at 630°C. The crystal structure of Ba₂(CN₂)(CN)₂ was determined from single-crystal X-ray investigations at room temperature and ?100°C; the isostructural Sr₂(CN₂)(CN)₂ was refined using powder methods (P6₃/mmc; Ba₂(CN₂)(CN)₂: a = 1 066.52(5) pm, c=696.82(3) pm; Sr₂(CN₂)(CN)₂: a = 1 035.91(1) pm, c = 664.23(1) pm; Z = 4). The crystal structure is a partially filled defect variant of the anti-NiAs structure type with a distorted hexagonal close packed arrangement of M²⁺-ions. All CN₂^2? and one quarter of the CN^? ions occupy 3/4 of the octahedrally coordinated interstices, the remaining cyanide anions are located at 3/8 of the tetrahedral sites. In the crystal structure the CN^? are coordinated to the cations both end-on and side-on. All anions can be distinguished by vibrational spectroscopy.     

High-precision direct determination of the Sr/Sr isotope ratio of bottled Sr-rich natural mineral drinking water using multiple collector inductively coupled plasma mass spectrometry

We describe a precise and accurate method for the direct determination of the ⁸⁷Sr/⁸⁶Sr isotope ratio of bottled Sr-rich natural mineral drinking water using multiple collector inductively coupled plasma mass spectrometry (MC-ICP-MS). The method is validated by the comparative analysis of the same water with and without cation-exchange resin purification. The work indicates that isobarically interfering elements can be corrected for when ⁸⁷Rb/⁸⁶Sr < 0.05 (Rb/Sr < 0.015), and that the matrix elements (Ca, Mg, K and Na) have no significant effect on the accuracy of the Sr isotope data. The method is simple, rapid, eliminates sample preparation time, and avoids potential contamination during complicated sample-preparation procedures. Therefore, the high sample throughput inherent to the MC-ICP-MS can be fully exploited.     

Synthesis,Crystal Structure and Properties of the Strontium Vanadate Fluoride Sr5(VO4)3F

The apatite‐type strontium vanadate fluoride Sr₅(VO₄)₃F was synthesized by standard solid‐state reaction method and grown by spontaneous crystallization flux method. It crystallizes in the hexagonal space group P6₃/m with lattice constants a = 9.988(4) Å, c = 7.415(6) Å, Z = 2. The structure consists of infinite three‐dimensional [Sr(2)₂(VO₄)₃]⁵⁺ framework with tunnels along the c axis, where Sr(1)²⁺ and F^– ions are filled. Functional groups in the structure have been identified by IR spectroscopy and the very high thermal stability up to 1400 °C has been identified by TG and DSC analyses. UV/Vis/NIR diffuse reflectance spectroscopy and first‐principle theoretical studies were also carried out to aid the understanding of optical properties and electronic structure.     

Problems in obtaining precise and accurate Sr isotope analysis from geological materials using laser ablation MC-ICPMS

This paper reviews the problems encountered in eleven studies of Sr isotope analysis using laser ablation multicollector inductively coupled plasma mass spectrometry (LA-MC-ICPMS) in the period 1995–2006. This technique has been shown to have great potential, but the accuracy and precision are limited by: (1) large instrumental mass discrimination, (2) laser-induced isotopic and elemental fractionations and (3) molecular interferences. The most important isobaric interferences are Kr and Rb, whereas Ca dimer/argides and doubly charged rare earth elements (REE) are limited to sample materials which contain substantial amounts of these elements. With modern laser (193 nm) and MC-ICPMS equipment, minerals with >500 ppm Sr content can be analysed with a precision of better than 100 ppm and a spatial resolution (spot size) of approximately 100 μm. The LA MC-ICPMS analysis of ⁸⁷Sr/⁸⁶Sr of both carbonate material and plagioclase is successful in all reported studies, although the higher ⁸⁴Sr/⁸⁶Sr ratios do suggest in some cases an influence of Ca dimer and/or argides. High Rb/Sr (>0.01) materials have been successfully analysed by carefully measuring the ⁸⁵Rb/⁸⁷Rb in standard material and by applying the standard-sample bracketing method for accurate Rb corrections. However, published LA-MC-ICPMS data on clinopyroxene, apatite and sphene records differences when compared with ⁸⁷Sr/⁸⁶Sr measured by thermal ionisation mass spectrometry (TIMS) and solution MC-ICPMS. This suggests that further studies are required to ensure that the most optimal correction methods are applied for all isobaric interferences.