Calcium-Strontium glasses

A table showing the colours imparted to the flame by salts of different metals is given in Section V.2(3). Carry out flame tests with the chlorides of sodium, potassium, calcium, strontium, and barium and record the colours you observe. Repeat the test with a mixture of sodium and potassium chlorides. The yellow colouration due to the sodium masks that of the potassium. View the flame through two thicknesses of cobalt glass the yellow sodium colour is absorbed and the potassium flame appears crimson. 

W.A. King, and J.E. Shelby, Strontium calcium aluminate glasses. Phys. Cltem. Glasses 37(1), 1-3 (1996). 

T.T. Bobrova, V.V. Moiseev, T.V. Permyakova and G.E. Sheshukova, Interaction of Alkaline Aluminosilicate Glasses with Molten Calcium, Strontium and Barium Nitrates, Izv. AN SSSR, Neorg. Mater. 9 (1973) 1416-1419. 

Place a few crystals each of the chlorides of sodium, potassium, calcium, strontium, and barium on watch glasses or glass plates and moisten them with a few drops of concentrated hydrochloric acid. 

Boron was known to the ancients in the form of borax, which was used for various types of glass. Boron is almost always found directly bound to oxygen and is difficult to prepare in pure form. In 1808 the ebullient chemist Sir Humphry Davy, whom we encountered as the discoverer of potassium and sodium (p. 324) as well as magnesium, calcium, strontium, and barium (p. 355), was just barely beaten (by 9 days) to the discovery of boron by the French chemists Joseph Louis Gay-Lussac and Louis Jacques Thenard. Yes, this is the same Gay-Lussac who proved (in 1802) that the volume of a gas is directly proportional to the temperature. (Jacques Charles, a French physicist, actually formulated this relationship some 15 years earlier, but... 

Barium-Calcium-Magnesium-Strontium Glasses/ Interconnect Interface... 

Calcium-Strontium-Based Glasses/Electrolytes Interfaces... 

Recently, Wilson Combe (1991) have studied the reactivity of magnesium, zinc, calcium and strontium boroaluminate glasses towards poly(acrylic acid) solutions. The controlling factor would seem to be the alumina content of these glasses which serves to moderate the setting rate of the cements. 

There is bound to be one problem with resin glass polyalkenoate cement. Because the matrix is a mixture of hydrogel salt and polymer, lightscattering is bound to be greater than in the conventional material. Moreover, the zinc oxide-containing glass of class II materials is bound to be opaque. This makes it difficult to formulate a translucent material and is the reason why their use is restricted to that of a liner or base. However, the class II material cited will be radio-opaque because it uses strontium and zinc, rather than calcium, in the glass. 

Glass-ionomers have been used in various areas of restorative dentistry since the mid 1970s. They were invented and originally described by Wilson and Kent [208], and consist of a basic glass powder and a water-soluble acidic polymer. The most widely used polymer is poly(acrylic acid), but acrylic/maleic acid copolymer is also widely used [209]. The glass powder is a complex calcium (or strontium) aluminofluorosilicate [210] that is typically at least partially phase separated. 

Wilson et al. [25] analyzed various brands of commercial cements and specified their possible composition, properties, and microstructure. Wilson et al. report the most representative and comprehensive data on commercial porcelain dental cements. These cements consist of powdered alumina-lime-silica glass mixed with phosphoric acid that formed a hard and translucent product. The starter glass powder consists of 31.5-41.6 wt% silica, 27.2-29.1 wt% alumina, 7.7-9.0wt% calcium oxide, 7.7-11.2 wt% sodium oxide, 13.3-22 wt% fluorine and small amounts of phosphorous and zinc oxides. Often very small amounts of magnesium and strontium oxides are also present. 

Viewing through cobalt-blue glass also allows calcium and strontium to be distinguished. In this case, calcium is light green in colour while strontium appears purple. 

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