Fluoroaluminate

A staining procedure for calcium fluoroaluminate (rare in normal clinker) was developed by microsco-pists in the 1960s at the PC A laboratories. It is based on the slightly different activities of C A and CjjA CaF. A polished surface of clinker, etched for 3 seconds in distilled water with a pH of 6.5 to 7.0, reveals C A as a bluish color. The surface is then given a second polish and a 30-second etch with a 0.1-molar potassium hydroxide solution that reveals CjjA CaF as a deep brownish-purple hue. Comments on each of these etches follow. 

Water etch (distilled water) in the pH range of 6.5 to 7.0 reacts rapidly with C A to form an interference film on the CjA that produces a bluish color when viewed through a reflected-light microscope. The procedure must be followed closely because other colors may appear with shorter etch times or slightly different acidities. Although the fluoroaluminate compound sometimes also reacts to produce a faintly visible brownish purple hue, this particular reaction is not used for positive identification. 

Potassium hydroxide is used for detection of fluoroaluminate. The section surface should be repolished after the water etch. The freshly polished clinker surface is then exposed to 0.1-molar potassium hydroxide solution for 30 seconds. The fluoroaluminate compound is identified by the definitive brownish purple interference color that is deeper in hue and sharper in outline than the one that, as mentioned, is sometimes visible after the 30 second distilled water etch. 

Experimental work on the microscopical staining method also reveals that fluorine-modified alite could 

CDTA is available from Hach, Inc., Loveland, Colorado, USA. 

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Of the fluoroaluminates known, cryoflte, ie, sodium hexafluoroaluminate [15096-52-2], Na AlF, has been an integral part of the process for production of aluminum. Recently, the mixtures of potassium tetrafluoroaluminate [14484-69-6], KAIF, and potassium hexafluoroaluminate [13575-52-5], K AlFg, have been employed as bra2ing fluxes in the manufacture of aluminum parts. 

The common structural element in the crystal lattice of fluoroaluminates is the hexafluoroaluminate octahedron, AIF. The differing stmctural features of the fluoroaluminates confer distinct physical properties to the species as compared to aluminum trifluoride. For example, in A1F. all corners are shared and the crystal becomes a giant molecule of very high melting point (13). In KAIF, all four equatorial atoms of each octahedron are shared and a layer lattice results. When the ratio of fluorine to aluminum is 6, as in cryoHte, Na AlF, the AIFp ions are separate and bound in position by the balancing metal ions. Fluorine atoms may be shared between octahedrons. When opposite corners of each octahedron are shared with a corner of each neighboring octahedron, an infinite chain is formed as, for example, in TI AIF [33897-68-6]. More complex relations exist in chioUte, wherein one-third of the hexafluoroaluminate octahedra share four corners each and two-thirds share only two corners (14). 

The toxicity of these fluoroaluminates is mainly as inorganic fluorides. The ACGIH adopted (1992—1993) values for fluorides as F is TLV 2.5 mg/m. The oral toxicity in laboratory animal tests is reported to be LD q rat 2.15 mg/kg (41). Because of the fine nature of the products they can also be sources of chronic toxicity effects as dusts. 

FLUOROALUMINATES, FLUOROBERYLLATES, FLUOROPHOSPHATES, FLUOROSILICATES, AND SIMILAR ENTRIES. 

In a reversal of the reaction with SiCl, aluminum can be introduced into the framework by reaction of the hydrogen or ammonium form with gaseous AlCl (36). Similarly, reaction with aqueous ammonium fluoroaluminates replaces framework-Si with Al (37). When alumina-bound high siUca 2eohtes are hydrothermaHy treated, aluminum migrates into framework positions and generates catalyticaHy active acid sites (38). The reaction can be accelerated by raising the pH of the aqueous phase. 

The validity of this approach can be demonstrated by the example of several complex fluoride compounds that exhibit ferroelectric properties, such as compounds that belong to the SrAlF5 family [402, 403]. The crystal structure of the compounds is made up of chains of fluoroaluminate octahedrons that are separated by another type of chains - ramified chains. Other examples are the compounds Sr3Fe2Fi2 and PbsWjOgFio. In this case, the chains of iron- or tungsten-containing octahedrons are separated from one another by isolated complexes with an octahedral configuration [423,424]. 

Dupuis, A., Israel, J.-P., Vignais, P.V. (1989). Direct identification of the fluoroaluminate and fluoroberyllate species responsible for inhibition of the mitochondrial F,- ATPase. FEBS Lett. 255,47-52. 

Marks TJ, Stern CL, Chen YXC (1997) Very large counteranion modulation of cationic metallocene polymerization activity and stereoregulation by a sterically congested (pefluoroaryl) fluoroaluminate. J Am Chem Soc 119 2582-2583... 

The weak binding of pl20GAP to Ras in the GTP-state was enhanced considerably when GTP (or GppNHp) was replaced by GDP and fluoroaluminate. In the a subunits of heterotrimeric G-proteins A1F, and GDP were shown to mimic a kind of transition state of GTP hydrolysis. For Ras this state could only be shown... 

Christie RA, Jordan KD (2005) -Body Decomposition Approach to the Calculation of Interaction Energies of Water Clusters 116 27-41 Clot E, Eisenstein O (2004) Agostic Interactions from a Computational Perspective One Name, Many Interpretations 113 1-36 Conley B, Atwood DA (2003) Fluoroaluminate Chemistry 104 181-193 Contreras RR, Su4rez T, Reyes M, Bellandi F, Cancines P, Moreno J, Shahgholi M, Di BUio AJ, Gray HB, Fontal B (2003) Electronic Structures and Reduction Potentials of Cu(II) Complexes of [N,N -Alkyl-bis(ethyl-2-amino-l-cyclopentenecarbothioate)] (Alkyl = Ethyl, Propyl, and Butyl) 106 71-79... 

Conley B, Atwood DA (2003) Fluoroaluminate Chemistry 104 181-193 Contakes SM, Le Nguyen YH, Gray HB (2007) Conjugates of Heme-thiolate Enzymes with Photoactive Metal-Diimine Wires. 123... 

Fig. 11. Modes of action of fluorine on osteoblastic cells, (a) Tyrosine phosphatase hypothesis in osteoblastic cells, fluoride ion directly inhibits tyrosine phosphatase. Inhibition of this enzyme enhances the tyrosine phosphorylation of signalling molecules induced by receptor tyrosine kinase, which leads to activation of the extracellular signal-regulated kinase (ERK) through the Ras pathway and enhanced cell proliferation, (b) G-protein hypothesis in osteoblast-like cells, fluoride ions form a complex with aluminum, probably fluoroaluminate, which interacts with guanosine 5 -diphosphate (GDP) to form guanosine 5 -triphosphate (GTP)-like molecule. Activation of the G, protein stimulates the tyrosine phosphorylation of signalling molecules by a yet unknown tyrosine kinase (Tyr Kin) and activation of the ERK kinase through the Ras pathway leads to enhanced cell proliferation. (Reproduced by permission of Elsevier from Ref. [175] ...

Fluorooluminatc of Potassium or Potassium Fluoroaluminate (Ger, Kryolith), K3AlFfiJ mw 258.27 crysts, mp 1025°, heat of formation 44.4kcal/foole prepd by heating KF ... 

Fliwrooluminote of Sodium or Sodium Fluoroaluminate (Cryolite), Na3ALF6. To the brief description given on p C567-L of Vol 3, the following uses may be added ... 

There are many fluorocomplexes of aluminum. The general formula for the fluoroaluminates is M I, I, a I- based upon A1F6 octohedra. which may share comers to give other ratios of A1 F than 1 6. Chloroaluminates of the type M lAlClj] are obtainable from fused melts. Aluminum ions form chloro-, bromo-, and iodo-complexes containing tetrahedral IALX41 ions. However, in sodium aluminum fluoride NaAlF4, the aluminum atoms are in the centers of octohedra of fluorine atoms in which the fluorine atoms are shared with neighboring aluminum atoms. 

Molten salts or ionic liquids (also referred to as fused salts by some authors) were among the very first media to be employed for electrochemistry. In fact, Sir Humphrey Davy describes electrochemical experiments with molten caustic potash (KOH) and caustic soda (NaOH) [1] as early as 1802 A wide variety of single molten salts and molten salt mixtures have been used as solvents for electroanalytical chemistry. These melts run the gamut from those that are liquid well below room temperature to those melting at more than 2000°C. The former present relatively few experimental challenges, whereas the latter can present enormous difficulties. For example, commercially available Teflon- and Kel-F-shrouded disk electrodes and Pyrex glass cells may be perfectly adequate for electrochemical measurements in ambient temperature melts such as the room-temperature chloroaluminates, but completely inadequate for use with molten sodium fluoroaluminate or cryolite (mp = 1010°C), which is the primary solvent used in the Hall-Heroult process for aluminum electrowinning. 

The course of the pollutant can be illustrated with other major pollutants. The oxidation of NADH or NADPH by PAN and Oa could remove cofactors required in enzymatic activity. The oxidation of free amino acids could generate inhibitors of metabolic reactions. The com-plexing of metals (such as Ca, Mg, Cu, Zn, or Fe) by fluoride could sequester metabolically significant cations. Perhaps the formation of a fluoroferrate or fluoroaluminate complex is metabolically significant. 

Keywords Tetrafluoroaluminate, Fluoroaluminates, Aluminates, G-proteins, Phosphate... 

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