## Octahedron Sentence Examples

- This is one of the Platonic solids, and is treated in the article Polyhedron, as is also the derived Archimedean solid named the "truncated tetrahedron"; in addition, the regular tetrahedron has important crystallographic relations, being the hemihedral form of the regular
**octahedron**and consequently a form of the cubic system. - All these are strikingly alike in appearance and general characters, differing essentially only in chemical composition, and it would seem better to reserve the name cerargyrite for the whole group, using the names chlorargyrite (AgC1), embolite (Ag(Cl, Bl)), bromargyrite (AgBr) and iodembolite (Ag(C1, Br, I)) for the different isomorphous members of the group. They are cubic in crystallization, with the cube and the
**octahedron**as prominent forms, but crystals are small and usually indistinct; there is no cleavage. - Ladenburg's prism formula would give two enantiomorphic ortho-di-substitution derivatives; while forms in which the hydrogen atoms are placed at the corners of a regular
**octahedron**would yield enantiomorphic tri-substitution derivatives. - The octahedral formula discussed by Julius Thomsen (Ber., 1886, 19, p. 2 944) consists of the six carbon atoms placed at the corners of a regular
**octahedron**, and connected together by the full lines as shown in (I); a plane projection gives a hexagon with diagonals (II). - Reduction to hexamethylene compounds necessitates the disruption of three of the edges of the
**octahedron**, the diagonal linkings remaining intact, or, in the plane projection, three peripheral linkages, the hexamethylene ring assuming the form (III); In 1888 J. - Marsh also devised a form closely resembling that of Thomsen, inasmuch as the carbon atoms occupied the angles of a regular
**octahedron**, and the diagonal linkages differed in nature from the peripheral, but differeng from Thomsen's since rupture of the diagonal and not peripheral bonds accompanied the reduction to hexamethylene. - Two parallel triangular faces are removed from a cardboard model of a regular
**octahedron**, and on the remaining six faces tetrahedra are then placed; the hydrogen atoms are at the free angles. - The native metal crystallizes in the cubic system, the
**octahedron**being the commonest form, but other and complex combinations have been observed. - In crystallography the icosahedron is a possible form, but it has not been observed; it is closely simulated by a combination of the
**octahedron**and pentagonal dodecahedron, which has twenty triangular faces, but only eight are equilateral, the remaining twelve being isosceles (see Crystallography). - It crystallizes in the cubic system, and well-developed crystals are of common occurrence; the usual form is the cube or the cubo-
**octahedron**(fig.). **OCTAHEDRON**(Gr.- The regular
**octahedron**has for its faces equilateral triangles; it is the reciprocal of the cube. - Philolaus, connecting these ideas, held that the elementary nature of bodies depends on their form, and assigned the tetrahedron to fire, the
**octahedron**to air, the icosahedron to water, and the cube to earth; the dodecahedron he assigned to a fifth element, aether, or, as some think, to the universe (see Plut. - The cube, the
**octahedron**, and the pentagonal dodecahedron. - 1 shows P the cube {100}, d the
**octahedron**{III }, and e the pentagonal dodecahedron {210}. - The crystals belong to the cubic system, generally assuming the form of the
**octahedron**(fig. - But they may, in accordance with the principles of crystallography, also occur in other forms symmetrically derived from the
**octahedron**, - for example, the cube, the 2-faced figure known as the rhombic dodecahedron (fig. - 2), or the 48-faced figure known as the hexakis-
**octahedron**(fig. - The
**octahedron**faces are usually smooth; most of the other faces are rounded (fig. - There is often a furrow running along the edges of the
**octahedron**, or across the edges of the cube, and this indicates that the apparently simple crystal may really consist of eight individuals meeting at the centre; or, what comes to the same thing, of two individuals interpenetrating and projecting through each other. - 5 shows how the
**octahedron**with furrowed edge may be constructed from two interpenetrating tetrahedra (shown in dotted lines). - 6) are united by contact along a surface parallel to an
**octahedron**face without interpenetration. - P the
**octahedron**faces; the latter are particularly well defined and have the form =% of equilateral triangles (fig. - Similar to the " etched figures " produced 7' by moistening an
**octahedron**of alum, and have probably been produced, like them, by the action of some solvent. - Diamond may break with a conchoidal fracture, but the crystals always cleave readily along planes parallel to the
**octahedron**faces: of this property the diamond cutters avail themselves when reducing the stone to the most convenient form for cutting; a sawing process, has, however, now been introduced, which is preferable to that of cleavage. - The Victoria, 180 carats, was cut from an
**octahedron**weighing 4572 carats, and was sold to the nizam of Hyderabad for £400,000. - A yellowish
**octahedron**found at De Beers weighed 4282 carats, and yielded a brilliant of 2882 carats. - The combination of these two forms produces a figure resembling an
**octahedron**, the angle between P and P' being 70° 72', corresponding to the angle 70° 32' of the regular**octahedron**. - Name Flussspat or Fluss.) Fluor-spar crystallizes in the cubic system, commonly in cubes, either alone or combined with the
**octahedron**, rhombic dodecahedron, four-faced cube, &c. The four-faced cube has been called the fluoroid. - The crystals are sometimes polysynthetic, a large
**octahedron**, e.g., being built up of small cubes. - Devon, notably near Liskeard, where fine crystals have been found, with faces of the six-faced
**octahedron**replacing the corners of the cube. - Nevertheless, holding that every dimension has a principle of its own, he rejected the derivation of the elemental solids - pyramid,
**octahedron**, icosahedron and cube - from triangular surfaces, and in so far approximated to atomism.