Metal hexagonal

Steel-gray crystalline brittle metal hexagonal crystal system atomic volume 13.09 cc/g atom three allotropes are known namely, the a-metaUic form, a black amorphous vitreous solid known as P-arsenic, and also a yellow aUotrope. A few other allotropes may also exist but are not confirmed. Sublimes at 613°C when heated at normal atmospheric pressure melts at 817°C at 28 atm density 5.72 g/cc (P-metallic form) and 4.70 g/cm (p-amor-phous form) hardness 3.5 Mohs electrical resistivity (ohm-cm at 20°C) 33.3xlCh (B—metallic polycrystalline form) and 107 (p—amorphous form) insoluble in water. 

Grayish metal hexagonal close-packed crystal system, lattice constant, a=2.286 A and c=3.584 A density 1.85 g/cm permeable to x-rays highly ductile modulus to weight ratio very high, elastic modulus 44.5 x 10 at 25°C (for hot-pressed block and sheet) melting point 1,287°C vaporizes at 2,471°C sound transmission velocity 12,600 m/sec reflectivity (white hght) 55% thermal neutron absorption cross-section 0.0090 barns/atom electrode potential, Be/Be2+(aq) 1.85 V electrical resistivity 3.36 x 10-i° ohm.m (at 20°C). 

Silvery metal hexagonal crystals density 8.559 g/cm melts at 1,411°C vaporizes at 2,561°C electrical resistivity 92.6 microhm-cm at 25°C Poisson s ratio 0.243 Young s modulus 0.644x10 kg/cm soluble in dilute acids. 

Silvery-white metal hexagonal close-packed structure density 9.84 g/cm melts at 1,663°C vaporizes at 3,402°C electrical resistivity 59 microhm-cm slightly paramagnetic thermal neutron cross section 108 barns soluble in acids. 

Hard silvery-white metal hexagonal close-packed crystal structure density 12.41 g/cm3 at 20°C melts at 2,334°C vaporizes at 4,150°C electrical resistivity 7.1 microhm-cm at 0°C hardness (annealed) 200-350 Vickers units Young s modulus 3.0x10 tons/in magnetic susceptibility 0.427 cm /g thermal neutron absorption cross section 2.6 barns insoluble in water, cold or hot acids, and aqua regia can be brought into aqueous phase by fusion of finely divided metal with alkaline hydroxides, peroxides, carbonates and cyanides. 

Silvery-gray metal hexagonal crystal structure malleable, ductile, and soft enough to be cut with a knife density 8.223 g/cm melts at 1,359°C vaporizes at 3,221°C resistivity llhxlCH ohm-cm at 25°C Young s modulus 5.75xl0n dynes/cm2 (from velocity of sound measurements) shear modulus 2.28 dynes/cm2 Poisson s ratio 0.261 thermal neutron absorption cross section, 46 barns insoluble in water soluble in acids. 

Silvery-white lustrous metal hexagonal close-packed structure density 9.321 g/cm3 at 25° melts at 1,545°C vaporizes at 1,947°C electrical resistivity 79 microhm-cm compressibility 2.6x10 cm /kg effective magnetic moment 7.62 Bohr magneton insoluble in water dissolves in concentrated acids. 

MESA at a liquid/liquid interface is not limited to two dimensions. Objects placed on a curved interface will assemble into a pseudo-3D system. The capillary forces between the objects are the same as those described for 2D MESA [ref. 5]. The curved interface is made by putting a drop of an immiscible liquid in another, isodense liquid the result is a sphere. The method can easily be extended to different shapes (catenoid, cylinder, cone) by distorting the shape of the drop [ref. 39]. The spherical assemblies in these experiments are made of metallic hexagons (100 pm sides 6 pm thick) with hydrophobic and hydrophilic sides [ref. 11]. Electrodeposition through lithographically defined molds fabricated metallic hexagonal rings (Fig. 4.16). Hydrophilic faces were introduced... 

Ordered removal of metal Hexagonal BaTiOs-type Unknown Known... 

Metal hexagonal close-packed structure, d 8.799 mp 146 P. Forms yellow-green salts,... 

Silvery-white metal. Hexagonal, close-packed structure,... 

Silvery-white metal hexagonal dose-packed structure-Slowty oxidizes in moist air. Available as bars, ribbons, wire and powder, mp 651°. bp 1100°. dM 1,738. Sp heat (20°) 0.245 cal/g. Heat of fusion 88 cal/g. Electrical resistivity 4.46 fiohm-cm, E° (aq) MgJ + /Mg —2.37 V. Reads very slowly with water at ordinary temp, less slowly at 100°. Reacts readily with dil adds with liberation of hydrogen reacts with aq solns of ammonium salts, forming a double salt. Reduces carbon monoxide, carbon dioxide, sulfur dioxide, nitric oxide, and nitrous oxide at a red heat. Burns in air continues to bum in a current of steam. Combines directly with nitrogen, sulfur, the halogens, phosphorus, and arsenic, Reacts with methyl alcohol at 200° giving magnesium methylate. 

Lustrous, hard metal hexagonal, cJose-packed structure. d 12.45. mp about 2450" bp about 4150", Sp heat (O ) 0,057 cal/g/°C. Does not react with acids, even aqua regia. Net oxidized by air in the cold on heating combines readily with oxygen the powdered metal forms the dioxide on ignit -mg in air. Supeficially attacked by coned alkaline hypochlorites, The powdered metal is attacked by chlorine above 200" by bromine between 300-700. Oxidized by fused alkali hydroxides. Forms alloys with platinum, palladium, cobalt, nickel, tungsten forms definite compds with zinc and with tin. 

Silvery-white, easily worked metal. Hexagonal close-packed structure, d 9.332. mp 1545". The solns of thulium salts show a characteristic absorption spectrum Exner,... 

PHYSICAL PROPERTIES soft, silver-white metal lustrous, malleable metal hexagonal, closepacked structure odorless very ductile tarnishes in air soluble in nitric acid and in ammonium nitrate solution insoluble in water usually found in combination with other elements such as oxygen (cadmium oxide), chlorine (cadmium chloride), or sulfur (cadmium sulfide) brittle at 80°C MP (321°C, 610°F) BP (765°C, 1409°C) DN (8.642 g/cm at 20°C) VP(lmmHg at 394°C) MOHS HARDNESS (2.0). 

Metallic, hexagonal selenium Is formed when any one of the other selenium modifications is heated above 130°C. 

The reaction of niobium with nitrogen at 10 Torr and 1000°C has been shown to form NbjNg on the surface of the metal. Hexagonal e-TaN has been converted into a high-pressure form 0-TaN at 20—100 kbar and 800—... 

Examination of the trends established by the rare earths and actinides is instructive. Lattice parameters for the rare-earth-like actinide hydrides are summarized in table 3. A comparison of the formula volumes of all the lanthanide and actinide dihydrides by Gibson and Haire (1990) is shown in fig. 8. From this perspective it is obvious that NpHj is anomalously small and CfH2 anomalously large. In any case, the non-metallic hexagonal phases are generally regular in terms of an actinide contraction and nearuniform cja ratios. 

AA )----This would involve bond rearrangement to a metallic hexagonal... 

---