Calcium fluoride lining

Of the various crystal matrices, the cubic calcium fluoride (CaF2), the lanthanum trihalides (LaFs, LaCl3, LaBr3) and ethylsulphate are popular host lattices. The spectra of rare earths with partly filled /-shells in doped crystals consist of very sharp lines, similar to those in atomic spectra, of closely spaced groups. Fig. 20 gives a summary of the crystal... 

Essentially this method solves the problems of the bomb lining, in this case calcium fluoride and of titanium reaction with the iron wall. This compoimd, because of its low melting point (1300° C.), which is many hundred degrees below that of either titanium or zirconium, would melt if it had to contain the pure fused metals. However, the zinc alloys with 20 to 30% zinc melt below 1300° C., thus making possible the use of calcium fluoride as a liner for the bombs. 

Example 14.1. The first-order diffraction of the Mo Ko 0.712 A line from a plane of calcium fluoride is observed as strong radiation at 6.48°. What is the distance between planes ... 

Fig. 13. Historical UV-VIS spectra of iodine adsorbed on chabazite and calcium fluoride compared to solid I2,12 vapor (broken line) and h dissolved in benzene. Reprinted from [17] with kind permission of R. Oldenbourg Verlag GmbH, Miinchen...

Excessive reaction between the container material and the products or reactants must be avoided, and this may impose a limit upon the peak temperature which is allowable, or upon the materials of reactor construction. Reactors take different forms and are made from or lined with a variety of refractory materials. Lime, magnesia, electrically fused dolomite, calcium fluoride, nickel, stainless-steel, molybdenum, tantalum, niobium or graphite have all been used, for different purposes. 

A small-scale technique only has been described, but the equipment was reasonably representative of a possible industrial process. Graphite, fused dolomite, pure magnesia or pure calcium fluoride have been used as reactor linings, inside a cylindrical steel casing, 18 in. deep by 8 in. diameter. Reactor lids consisted of either screw caps or bolted flanges and provision was made for argon purging and evacuation prior to initiation. 

Calcium fluoride (Fp. 1423 °C solubility in water 0,02 g/1 at 20 °C) is employed in aluminium metallurgy, brake lining, glass manufacturing, enamel [63] and glazing frits production, dental applications and in the production of welding agents. 

Bone is a porous tissue composite material containing a fluid phase, a calcified bone mineral, hydroxyapatite (HA), and organic components (mainly, collagen type). The variety of cellular and noncellular components consist of approximately 69% organic and 22% inorganic material and 9% water. The principal constiments of bone tissue are calcium (Ca ), phosphate (PO ), and hydroxyl (OH ) ions and calcium carbonate. There are smaller quantities of sodium, magnesium, and fluoride. The major compound, HA, has the formula Caio(P04)g(OH)2 in its unit cell. The porosity of bone includes membrane-lined capillary blood vessels, which function to transport nutrients and ions in bone, canaliculi, and the lacunae occupied in vivo by bone cells (osteoblasts), and the micropores present in the matrix. 

Standard Response Line Prepare as directed under Fluoride in the monograph for Calcium Phosphate, Dibasic, except use 3.0 mL of hydrochloric acid instead of 2.0 mL. 

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