Sparingly soluble mineral crystals

Colourless crystals m.p. 50 C, b.p. 301 C. Basic and forms sparingly soluble salts with mineral acids. Prepared by the reduction of 1-nitronaphthalene with iron and a trace of hydrochloric acid or by the action of ammonia upon l-naphlhol at a high temperature and pressure. 

OrthoteUuric Acid. The white crystals of orthoteUuric acid [7803-68-1], H TeO, are sparingly soluble in cold water and easUy soluble in hot water and mineral acids, with the exception of HNO3. It is made by oxidizing Te or Te02, for example by refluxing with H2O2 in concentrated H2SO4. It... 

Red tetragonal crystal density 4.46 g/cm melts at 1,127°C vaporizes around 1,400°C sparingly soluble in water soluble in warm mineral acids decomposes in boiling water. Tetrahydrate is red orthogonal crystal density 2.22 g/cm3 decomposes on heating soluble in water di- and trihydrates are soluble in water. 

The salts of the series are bright red crystalline bodies. They are soluble in water, neutral in reaction, and dilute mineral acids do not transform them into aquo-salts. The least soluble member of the series is the sulphate [(NH3)4Co (OH)2 Co(NH3)4](S04)a.2H30, which is prepared by heating hydroxo-aquo-tetrammino-cobaltic sulphate at 100° C. till it is constant in weight. The mass is extracted with water and the sparingly soluble sulphate collected and dried. The crude product so obtained is converted into the chloride and an aqueous solution of this then treated with a solution of sodium sulphate, when a crystalline precipitate of the diol-sulphate is obtained. It is collected, washed with water, alcohol, and finally with ether. It forms small red needle-shaped crystals which contain two molecules of water of hydration. 

Sparingly soluble in cone, mineral acids, except hydrofluoric acid when freshly precipitated, soluble (withformationof a complex) in a mixture of H3PO4, oxalic acid and cone. HaS04. An acid-soluble, white pero compound is formed when a cold suspension of the phosphate is reacted with an NaOH-Na a solution and then digested at 70°C. ZrPaO crystallizes in the cubic K 61 lattice. 

Difficulties arise, not so much in explaining why mineralization readily and regularly occurs in certain tissues, but rather why other tissues, which resemble them in many ways, do not normally mineralize. Thus it is relatively easy to explain how crystals of a very sparingly soluble substance such as hydroxyapatite can be formed in bone, on the basis of the concentrations of calcium and phosphate ions present in blood these are sufficiently high to permit small crystals of biological apatite to grow at the expense of ions in solution. It is more difficult to appreciate why, under apparently similar conditions, a tissue such as skin which, like bone, contains... 

The barium oxide obtained in this way is not pure, but contains particles of charcoal as well as impurities coming from the mineral. It is very suitable, however, for the manufacture of barium hydroxide, into which it is converted by treatment with water. Barium hydroxide is extremely soluble in hot water, but sparingly so in cold water, from which it separates in flake-like crystals of the composition Ba(0H)2-8H20. 

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