Calcium refractive index

Alternative refractive index of 1.523 for dihydrate and 1.575 for anhydrous calcium sulfate. 

Pure compound is white cubic crystal or powder impure or luminous calcium sulfide is pale yellow to light gray bitter taste odor of H2S in moist air hygroscopic refractive index 2.137 hardness 4.0 Mohs density 2.59 g/cm melts at 2,525°C slightly soluble in water insoluble in alcohol soluble in acids with decomposition. 

Clarification by removal of casein with such agents as calcium chloride, acetic acid, cooper sulfate, or rennin has often been employed to obtain a serum more suitable for refractometric measurements. Obviously the composition, and hence the refractive index, of such sera will depend on the method of preparation. Furthermore, some of the serum proteins may be precipitated with the casein by some of the agents used, particularly if the milk has been heated. Refractive index measurements of such sera are not generally considered as satisfactory as freezing point measurements for detection of added water (David and MacDonald 1953 Munchberg and Narbutas 1937 Schuler 1938 Tell-mann 1933 Vleeschauwer and Waeyenberge 1941). Menefee and Overman (1939) reported a close relation between total solids in evaporated and condensed products and the refractive index of serum prepared therefrom by the copper sulfate method. Of course, a different proportionality constant would hold for each type of product. 

Calcium Boroarsenate occurs in New Jersey as the mineral cahnite4 (see p. 14) it forms white, vitreous, tetragonal sphenoids, occurring in characteristic interpenetrating twins. The refractive index is 1-662. 

Other methods that have been used in determination of the amount of moisture in coke include (1) extraction of coke using anhydrous methanol and the addition of calcium hydride with coal constituents (CaH2) from which the amount of released heat is measured, and (2) extraction of coke using anhydrous dioxan and measurement of the refractive index of the solution to determine its water content. Application of these methods to coal may be subject to error because of (1) interaction of the coal (in contrast to coke) with the calcium hydride, leading to chemical errors, and (2) the influence of extractable constituents on the refractive index of the dioxan. 

Calcium dihydrogen orthophosphate 1-hydrate crystallizes as large, white, shining, triclinic plates which may be up to 1 mm. in diameter. The refractive indexes for the crystals are 1.528, 1.518, and 1.501.1 No increase in weight is detectable when calcium dihydrogen orthophosphate... 

Monetite forms white triclinic (1) crystals with refractive indexes 1.63, 1.61, 1.60.3f At red heat it is dehydrated to calcium pyrophosphate. 

Chromatographic System Use a liquid chromatograph equipped with a refractive index detector that is maintained at a constant temperature and a 9-mm x 30-cm column packed with a strong cation-exchange resin, about 9 pm in diameter, consisting of sulfonated cross-linked styrene-divinylbenzene copolymer in the calcium form (Aminex HPX-87c, or equivalent). Maintain the column temperature at 85° + 0.5°, and the flow rate of the Mobile Phase at about 0.5 mL/min. Chromatograph the Standard Preparation, and record the peak responses as directed under Procedure. Replicate injections show a relative standard deviation not greater than 2.0%. 

Fig. 2.1 shows the phase diagram. For clarity, the polymorphism of C3S and the distinction between a - and a L-C2S are omitted. Calcium oxide (CaO) has the sodium chloride structure, in which all ions are octahedrally coordinated the unit cell is cubic, with a = 0.48105 nm, space group Fm3m, Z = 4, = 3345 kgm (S5). The refractive index is 1.837 (W3). 

Preparation of 2-Allylphenol. The allyl ether is boiled in a flask under a reflux tube, the course of the rearrangement being conveniently followed by noting the refractive index at frequent intervals. When nu has risen to 1.55 (five to six hours) the rearrangement is substantially complete with the minimum formation of undesirable by-products. To separate a small amount of 2-methyldihydrobenzofuran, the product is dissolved in tivice its volume of 20% sodium hydroxide solution and extracted twice with petroleum ether (30-60°), from which the dihydro-benzofuran residue may be obtained by distillation. Ether should not be used for this extraction as it removes some of the phenol from the alkaline solution. The alkaline solution is acidified and the phenpl extracted with ether the extract is dried over calcium chloride and distilled under diminished pressure. A 73% yield of material boiling at 103-105.5°/19 mm., no 1.5445, is obtained. 2-Allylphenol is a colorless liquid, of guaiacol-like odor, with the following properties b.p. 220°/ 760 mm., 99°/12 mm., nf) 1.5453. ... 

Close the screw clamp, invert the tube and separate the ether layer as directed on pages 115-117. The ether layer is allowed to remain in the reaction tube. Add about 0.2 g of calcium chloride to the ether mixture and allow to stand for 15 minutes. Most of the ether is removed by distilling directly from the large tube (see Figure 39). When the amount of liquid in the tube is about 5 ml, it is transferred to a regular small distilling tube and fractionated (Figure 25). The fraction which boils at 108-112° is collected. The jfield is 1.0-1.3 g. If a refractometer is available determine the refractive index of your product. 

Mix and place in the distilling tube, arranging the thermometer so that it nearly touches the bottom of the tube. Heat with a free flame to 285-290°. Move the burner to and fro so that the heat is directed towards all sides of the tube. When the mixture has melted, adjust the flame so that the temperature remains about 290°. If the temperature is allowed to rise above 295°, adipic acid distills over and the side tube becomes clogged. Continue the distillation until only a small residue remains in the flask. Add 2 ml of saturated salt solution to the receiving tube, insert the separatory stopper, shake gently, and then withdraw the lower aqueous layer. Dry with 0.5 g of anhydrous calcium chloride and distill. The yield is 1.3-1.5 g. If a refractometer is available, determine the refractive index of your product. 

Calcium hydroxide is a product new to the market. There have been, in past, positive scientific reports of its usefulness. The benefits of calcium hydroxide over calcium carbonate are its functionality, particle shape (more spherical and thus less abrasive to the equipment) (Figure 2.18), its lower density (decreases the density of product and lowers the price), a refractive index closer to many polymers, and its lower cost (approximately half of the price of calcium carbonate). The manufacturing equipment includes an excitement chamber, metered conveying, pneumatic transportation, flash drying, classification, and silo storage. The manufacturer delivers product to customers by its own silo-trucks. 

Figure 12.5 Ligand-exchange chromatography of sugars and sugar alcohols [reproduced with permission from J. Schmidt, M. John and C. Wandrey, J. Chromatogr., 213, 151 (1981)]. Conditions column, 90cm x 7.8 mm i.d. stationary phase calcium-loaded cation exchanger mobile phase Imimin water temperature 85°C refractive index detector.

Filler Opacify compound, increase hardness, reduce cost Changes refractive index and reflective properties, adds bulk to compound Calcium carbonate, magnesium carbonate, barium sulfate, carbon or glass fibres... 

Fillers must be free of sulfur-containing impurities, iron, and zinc. In order to minimize reduction in clarity, fillers should have a fine particle size and an index of refraction close to that of the PVC resin. If opacity is desired, however, high refractive index fillers such as talc or calcium carbonate can be used to minimize the amounts of the more expensive titanium dioxide opacifying pigment required. 

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