Is the Hexacyanoferrate(II) Anion Stable in Aqueous Solution? A Combined Theoretical and Experimental Study

A combined theoretical and experimental study was performed to elucidate the structural and dynamical properties of the isolated aqueous hexacyanoferrate(II) ion as well as in the presence of potassium counterions. It is shown that in absence of counterions, the highly negatively charged hexacyanoferrate(II) complex is not stable in aqueous solution. However, if the high negative charge is compensated by potassium counterions, a stable complex is observed, which is proven by theoretical simulations as well as by extended X-ray absorption fine structure (EXAFS) experiments. From the simulation it is found that potassium ions surrounding the complex are highly mobile and thus cannot be observed via EXAFS experiments. The structure of aqueous hexacyanoferrate(II) in the presence of potassium ions is identical to that of the solid-state structure, but the mobility of potassium ions is significantly increased in the liquid. These highly mobile potassium ions circulating the complex are the reason for the very short lifetime of hydrogen bonds between solvent water molecules and cyanide ligands being on the femtosecond scale

Factors controlling the water quality of rock glacier springs in European and American mountain ranges

Rock glaciers (RGs) provide significant water resources in mountain areas under climate change. Recent research has highlighted high concentrations of solutes including trace elements in RG-fed waters, with negative implications on water quality. Yet, sparse studies from a few locations hinder conclusions about the main drivers of solute export from RGs. Here, in an unprecedented effort, we collected published and unpublished data on rock glacier hydrochemistry around the globe. We considered 201 RG springs from mountain ranges across Europe, North and South America, using a combination of machine learning, multivariate and univariate analyses, and geochemical modeling. We found that 35 % of springs issuing from intact RGs (containing internal ice) have water quality below drinking water standards, compared to 5 % of springs connected to relict RGs (without internal ice). The interaction of ice and bedrock lithology is responsible for solute concentrations in RG springs. Indeed, we found higher concentrations of sulfate and trace elements in springs sourcing from intact RGs compared to water originating from relict RGs, mostly in specific lithological settings. Enhanced sulfide oxidation in intact RGs is responsible for the elevated trace element concentrations. Challenges for water management may arise in mountain catchments rich in intact RGs, and where the predisposing geology would make these areas geochemical RG hotspots. Our work represents a first comprehensive attempt to identify the main drivers of solute concentrations in RG water

Time properties of MWPC using electronegative gases, and their efficiency of detection for normal and abnormal particles (quarks)

The efficiency for detection of fractionally charged particles of multiwire proportional chambers using electronegative gases has been investigated, using a model to simulate the ion production and drift in a MWPC and comparing the results with experimental data. (10 refs)

A search for fractionally charged particles at the CERN intersecting storage rings

Final results of a search for fractionally charged particles at the CERN Intersecting Storage Rings are reported. Several independent scintillation counter, multiwire proportional chamber telescopes simultaneously sampled c.m. production angles from 0 degrees to 90 degrees . The experiment was sensitive to particles of electric charge in the range 0.1e< mod Q mod <0.8e, with velocities greater than 0.25c and with masses up to, in principle, 47 GeV/c/sup 2/. No such particles were observed among the products of 1.2*10/sup 10/ proton- proton interactions at s=2830 GeV/sup 2/. The cross section limit for the production of quark-antiquark pairs of charge mod Q mod =/sup 1 ///sub 3/e or /sup 2///sub 3/e in the reaction pp to ppqq, at s=2830 GeV/sup 2/, is sigma <or approximately=8*10/sup -35/ cm/sup 2/ for quark masses up to approximately 20 GeV/c/sup 2/. (30 refs)

A search for quarks at the CERN intersecting storage rings

No quark candidates have been seen among 0.6*10/sup 9/ charged particles at the ISR. The corresponding cross section limit for charge /sup 1///sub 2/(/sup 2///sub 3/) is <or=3(6)*10/sup -34/ cm/sup 2/ for quark masses up to 22(13) GeV, assuming (P/sub T/)=0.4 GeV/c. (9 refs)