Bipyramidal crystals

A A Diethylamino)phenol. This derivative (16) forms rhombic bipyramidal crystals. Industrial synthesis is analogous to the previously described synthesis of 3-(/V,/V-dimethy1amino)pheno1 from resorciaol and diethylamiae, by reaction of 3-(Ai,A/-diethylamiQo)benzenesulfonic acid with sodium hydroxide, or by alkylation of 3-amiaophenol hydrochloride with ethanol. 

Succinic acid is absorbed from aqueous solutions by anion-exchange resins or active carbon (9—11). Succinic anhydride forms rhombic pyramidal or bipyramidal crystals. It is relatively insoluble in ether, but soluble in boiling chloroform and ethyl acetate. Succinic anhydride reacts with water and alcohols, giving the acid and monoesters, respectively. 

Hanssen s Acid, CjgHjoOiNj. 2 or IHjO. This acid, obtained by the oxidation of either strychnine or brucine and certain of their derivatives as described above, forms cubical or bipyramidal crystals, m.p. 311° (dec.), — 116-3° (HgO), and yields a dihydro-derivative, CigHjaO Nj,... 

Purified MeHNL was crystallized by the sitting-drop vapor-diffusion method. The 10-20 mm bipyramidal crystals formed were cross-linked with glutaraldehyde and used as biocatalyst for the synthesis of optically active cyanohydrins. The cross-linked crystals were more stable than Celite-immobilized enzymes when incubated in organic solvents, especially in polar solvents. After six consecutive batch reactions in dibutyl ether, the remaining activity of the cross-linked crystals was more than 70 times higher than for the immobilized enzymes. Nevertheless, the specific activity of the cross-linked crystals per milligram protein was reduced compared with the activity of Celite-immobilized enzymes [53],... 

The rhombic bipyramidal crystals of potassium sulphate form an isomorphous group with those of the corresponding salts of rubidium and csesium. The axial ratios and mol. vol. are indicated in Table XXXVI the axial ratios and topical parame.ters of the three last-named salts were determined by A. E. H. Tutton.26... 

The clear transparent rhombohedral crystals of a-Na2C03.7H20 are unstable and readily pass into the rhombic bipyramidal crystals of /3-Na2C03.7H20. The crystals of the a-salt Boon become milk-white owing to the formation of the decahydrated salt by the re-crystallization of the heptahydrated carbonate moist with the adherent water. The solubility curve is indicated in Eig. 68. H. Lowel prepared the unstable rhombohedral or a-salt in the following maimer ... 

Hibbert [15] assumed that the labile form of nitroglycerine belongs to the triclinic system, while according to Flink [19] the stable form has orthorhombic bipyramidal crystals. 

Bismuth oxychloride (bismuth oxide chloride) with the formula BiOCI was the first synthetic nontoxic nacreous pigment. Its production in form of monocrystals takes place by hydrolysis of acidic bismuth salt solutions in the presence of chloride ions. The desired pigment crystal quality can be controlled by varying the precipitation conditions (concentration, temperature, pH, pressure, addition of surfactants). The virtually tetragonal bipyramidal crystal structure is thereby modified into a flat platelet. 

Bismuth oxychloride flat tetragonal bipyramidal crystals 5-30 100-700 7.7... 

Blackish-brown, orthorhombic, bipyramidal crystals. Practically insol in water, ethyl acetate sol in HNOs, HCl. 

Monohydrate, orthorhombic bipyramidal crystals from water, mp 220". 

Dark, reddish-brown, orthorhomhic bipyramidal crystals, dj° 1.972. Sol in water. 

Anhydrous form, salt cahe (technical grade). Powder or orthorhombic bipyramidal crystals, mp about 800°. d 2.7. Sol in about 3.6 parts water. Max soly at 33° 1 in 2. 

Dihydrate, orange-yellow, rhombic, bipyramidal crystals. Stable to 100. Dec before all HjO of hydration lost. Freely sol in water sol in alcohol, ether. 

Ammonium pentachlorozincate EINECS 238-688-1 Triammonium pentxhlorozincate(3-) Zinc ammonium chloride Zincale(3-) pentachloro-, triammonium. Used in welding and soldering flux, in dry batteries and galvanizing. Bipyramidal crystals sublimes 340 d... 

---