A Study of the Mn, Co and Ni Environment in the As-synthesized and Rehydrated-calcined Aluminophosphate with Chabazite-like Topology

Diffuse-reflectance spectroscopy (DRS), X-ray absorption near-edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) methods are applied to an investigation of Mn, Co and Ni local environments in MnAlPO, CoAlPO, and NiAlPO materials with chabazite-like topology. For all three products, insertion of the transition metals into tetrahedral Al-sites has been found. Calcination and rehydration of the as-synthesised materials cause a change of the oxidation number and co-ordination geometry of Mn and Co, while the oxidation and co-ordination number of Ni remain unaffected

A Physico-chemical Study of the Interaction of Cobalt(II) Ion with Ciprofloxacin

Reaction between the quinolone antibacterial agent Ciprofloxacin (abbreviation cfH) and Co11 in aqueous medium was studied. The ability of Ciprofloxacin to form metal complexes is highly dependent on the pH value of the solution. UV spectroscopy and solubility of Ciprofloxacin • HC1 were used to determine the optimal conditions for complex isolation in the pH region between 5 and 10, where the solubility of quinolones is very low. The isolated complex [Co(cf)2]× 3H20 was characterized by elemental analysis, FAB-MS, TG analysis, IR spectroscopy and magnetic measurements. Cobalt K-edge EXAFS was used for the Identification of the Co site in the complex

X-ray absorption spectroscopy and related techniques

In the extensive field of X-ray diagnostic techniques, nowadays mostly implemented on synchrotron X-ray sources, the X-ray absorption methods offer a relatively simple tool for structural analysis of materials. The advantage of the methods is the sensitivity to chemical species and the insensitivity to the long-range order. An overview of various detection techniques is given together with the discussion of accuracy of the method with regard to the spatial resolution and the possible contamination by intra-atomic contributions, the multielectron photoexcitations.Znotraj razsežnega področja diagnostike snovi z rentgensko svetlobo, ki se dandanes vse bolj izvaja ob sinhrotronskih izvirih, ponujajo metode rentgenske absorpcije razmeroma preprosto orodje za strukturno analizo materialov. Med prednosti metode štejemo, da jo lahko uglasimo na določen kemijski element in da je neobčutljiva na urejenost dolgega dosega. Podan je pregled različnih detekcijskih izpeljank metode in z njim natančnost glede na krajevno ločljivost in glede na napake, ki izvirajo od intra-atomskih učinkov, t.j. večelektronskih fotoekscitacij

Determination of Valence States of Chromium in Calcium Chromates by Using X-ray Absorption Near-Edge Structure (XANES) Spectroscopy

Calcium chromates with the empirical formulas Ca10Cr6−O25, Ca3Cr2O8, and Ca5Cr3O12, which form at temperatures >900°C at CaO:Cr2O3 molar ratios of geqslant R: gt-or-equal, slanted3 in an oxidation atmosphere have been synthesized in the pure state. X-ray absorption near-edge structure (XANES) spectroscopy has been used to determine the average valence state of chromium in the samples. The presence of unusual chromium valence states, 4+ and 5+, which was proposed via X-ray diffractometry studies, is strongly supported

High-resolution X-ray absorption spectrometry of atomic vapors

A measurement of an x-ray absorption spectrum of a monatomic sample yields pure atomic absorption essential for the EXAFS (Extended X-ray Absorption Fine Structure) analysis in cases of a weak structural signal. A construction of an absorption cell to contain vapor sample takes into account specific properties of the investigated element. Metal-vapor absorption cells for the elements K, Zn, Rb, Cd, Cs, and Hg are presented and comments are made on the use of materials and the operating mechanisms of the cells.Z meritvijo rentgenskega absorpcijskega spektra enoatomnega vzorca dobimo atomsko absorpcijo, ki je nujna za analizo EXAFS (Extended X-ray Absorption Fine Structure - podaljšana drobna struktura rentgenskih absorpcijskih robov), kadar je strukturni signal šibek. Izdelava absorpcijske celice, v kateri hranimo uparjeni vzorec, je odvisna od lastnosti preiskovanega elementa. V prispevku so predstavljene absorpcijske celice za kovinske pare K, Zn, Cd, Rb, Cs in Hg, posebna pozornost pa je namenjena delovanju celic in materialom, ki so bili uporabljeni pri njihovi izdelavi

EXAFS and IR analysis of electrochromic NiOxNiO_x/NiOxHyNiO_xH_y thin films

Electrochromic (EC) thin films of $NiO_x$ and $NiO_xH_y$ are prepared by sol-gel method from nickel chloride precursor and deposited onto a suitable substrate by dip-coating technique. The development of the structure with thermal treatment is investigated by EXAFS and IR spectroscopy in two series of films, with high and low concentration of chloride as counter ions. In the former, the predominant structure before thermal treatment is nickel hydroxide. The baking induces condensation, yet with no trace of NiO. In the latter group, colloidal particles are indicated, on which acetate groups are adsorbed or coordinated. At the maximum EC-response the formation of NiO grains is established by EXAFS and IR.Elektrokromne tanke plasti $NiO_x$ in $NiO_xH_y$ smo pripravili z metodo sol-gel iz nikelj-kloridnega prekurzorja in jih s tehniko potapljanja nanesli na ustrezno podlago. Razvoj strukture s temperaturo obdelave smo spremljali s spektroskopijama EXAFS in IR pri dveh serijah filmov z visoko oz. nizko koncentracijo kloridnih proti-ionov. V prvi pred termično obdelavo prevladuje struktura nikljevega hidroksida. Segrevanje nato izzove kondenzacijo, vendar brez sledov NiO. V drugi seriji so prisotni koloidni delci, na katere so adsorbirane acetatne skupine. Z obema spektroskopskima metodama smo pri plasteh z največjim elektrokromnim odzivom ugotovili prisotnost strukture nikljevega oksida

X-ray absorption spectroscopy and related techniques

In the extensive field of X-ray diagnostic techniques, nowadays mostly implemented on synchrotron X-ray sources, the X-ray absorption methods offer a relatively simple tool for structural analysis of materials. The advantage of the methods is the sensitivity to chemical species and the insensitivity to the long-range order. An overview of various detection techniques is given together with the discussion of accuracy of the method with regard to the spatial resolution and the possible contamination by intra-atomic contributions, the multielectron photoexcitations