Aqua Survey

First, the structure should explain the data. Apart from the energy or target function value returned by the refinement program, this check can be performed with some independent programs (e.g., AQUA/PROCHECK-NMR [90], MOLMOL [91]). The analysis of the deviations from the restraints used in calculating the structures is very useful in the process of assigning the NOE peaks and refining the restraint list. As indicators of the quality of the final structure they are less powerful, because violations have been checked and probably removed. A recent statistical survey of the quality of NMR structures found weak correlations between deviations from NMR restraints and other indicators of structure quality [88]. 

Fig. 3. Distribution of Cu and Au in B and C horizon soil west of the north zone, Shiko Lake. C horizon geochemical data are from BCGS studies by Lett Doyle (2009) and a Novagold Resources till survey by Petsel (2006). Gold abundance in the C horizon samples was determined by an aqua regia digestion and instrumental analysis.

KEYWORDS aqua regia digestion, certified reference materials, analysis of variance, Trinational soil survey... 

ABSTRACT The results of a soil geochemical survey of the Canadian Maritime provinces and the northeast states of the United States are described. The data presented are for the <2-mm fraction of the surface layer (0-5 cm depth) and C horizons of the soil. Elemental determinations were made by ICP-MS following two digestions, aqua regia (partial dissolution) and a strong 4-acid mixture (near-total dissolution). The preliminary results show that Hg and Pb exhibit elevated abundances in the surface layer, while As and Ni exhibit abundances that can be attributed to the geological provenance of the soil parent materials. 

In the following, a survey will be given of structures of complexes derived from solution diffraction data. The methods used and the approximations involved will be discussed. The basic theory of diffraction in solutions has been covered in several previous reviews (5, 7, 8) and will not be given here. Structure determinations of aqua complexes of metal ions in aqueous solutions have also been extensively reviewed (7-11) and will be discussed here only when they are of interest for the structures of complexes containing other ligands. 

In systems containing no anion other than fluoride, mixed aqua-fluorometalates mainly with [MF5(H20)] and [MF4(H20)2] are frequently formed. Therefore the possibility of H-bond formation plays an important role see Hydrogen Bonding Dihydrogen Bonding). The most investigated systems contain Al , Fe , Mn (surveys in Refs. 18, 113), and Aluminium compounds are... 

The recorded differences in adsorption capability indicate a different mechanism of interaction between the carbon surface and the ionic metal species pre.sent in the aqueous solution (aqua and hydroxy complexes, hydroxide ions, and electronegative complexes). To discover the state of the adsorbed. species, some independent measurements of the surface layer of adsorbent were carried out. The selected carbon samples were studied by the XPS method in powdered form following copper uptake (Figs. 42 and 43). Several peaks attributable to carbon, oxygen, nitrogen, and copper were present. The XPS survey spectra of the initial modified carbons (before adsorption) were discussed in the previous section. The surface elemental composition estimated from XPS data for modified D43/1 car-... 

SYNTHESIS, PURIFICATION AND CHARACTERIZATION OF COORDINATION COMPOUNDS - including a detailed survey of aqua metal ions, the use of solvents, chromatographic methods, and crystal growth techniques. 

Fig. 17.35 Lake Vostok in East Antarctica is the largest of about 160 subglacial lakes that have been discovered by radar echo surveys. The lake is about 300 km long and about 50 km wide. It is covered by 3,700 m of ice and occupies a tectonic rift that is bounded by deep faults. Lake Vostok was named after the Russian research station that is located close to the southern end of the subglacial lake. Lake Sovetskaya and 90°E Lake, which are located close to the 90°E Meridian may also occupy rift basins (Adapted from MODIS Mosaic of Antarctica acquired by NASA s satellites Terra and Aqua between November 20, 2003 and February 29,2004)...

Chemical Properties. Ruthenium is not attacked by acids or alkali even under oxidizing conditions (aqua regia). By heating in air above 800 °C Ru forms the oxides RuO and RUO2 above 1100°C Ru forms RuOs which vaporizes. Detailed survey about the chemical properties is given in [ 1.218,218]. 

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