| 单词 | octahedron |
| 例句 | The 170-carat Black Prince’s Ruby, a centerpiece of the British Crown Jewels, is, in fact, a red spinel octahedron, most likely from the mines of Badakhshan. Special Report: Jewelry: Restoring the Luster to a Once-Loved Gem 2011-05-12T13:49:21Z All of this is enough to send any mother into a spiral of madness, or an even more elaborate shape — a Möbius strip of insanity, an octahedron of derangement. A Chilling Debut Novel Puts Mothers Under Surveillance and Into Parenting Rehab 2022-01-11T05:00:00Z Octahedral complexes have a coordination number of six, and the six donor atoms are arranged at the corners of an octahedron around the central metal ion. Chemistry 2019-02-14T00:00:00Z Adjacent octahedrons were rotated 90 degrees from one another and connected at the corners. A Flexible Fabric Could Harden into a Temporary House or Bridge 2021-08-20T04:00:00Z The Feb. 22 Local Living article “Give your bookshelf a little more character” included a geometric object labeled “large octahedron.” Opinion | Perk up that bookshelf with a nice rhombicuboctahedron 2018-03-02T05:00:00Z The second is a specific bonding geometry, which is achieved when octahedra formed from metal and oxygen ions share their edges to form a honeycomb lattice. The two faces of a magnetic honeycomb 2018-02-13T05:00:00Z These are the five convex polyhedra—tetrahedron, cube, octahedron, dodecahedron, and icosahedron—that are made of congruent regular polygons. Justin Curry's Favorite Theorem 2017-12-09T05:00:00Z As six ligands approach the metal ion along the axes of the octahedron, their point charges repel the electrons in the d orbitals of the metal ion. Chemistry 2019-02-14T00:00:00Z These materials contained the rings of classic chain mail but also octahedrons with different angles or fewer cross struts. A Flexible Fabric Could Harden into a Temporary House or Bridge 2021-08-20T04:00:00Z Scientists created a platinum alloy blended with nickel, forming three-dimensional shapes at the nanometer scale -- in this case, octahedrons. Cheap Fuel Cells, Hold the Platinum 2013-06-20T15:15:02.123Z It is white, transparent, very astringent, and crystallizes easily in octahedrons. Webster's Unabridged Dictionary 2012-03-24T02:00:23.513Z The tetrahedron, octahedron, and icosahedron are made of four, eight, and twenty, respectively, equilateral triangles, the cube of six squares, and the dodecahedron of twelve regular pentagons. Justin Curry's Favorite Theorem 2017-12-09T05:00:00Z Well-developed crystals are of common occurrence; they usually have the form of the regular octahedron, sometimes in combination with the cube and the rhombic dodecahedron. Encyclopaedia Britannica, 11th Edition, Volume 7, Slice 8 "Cube" to "Daguerre, Louis" 2012-01-31T03:00:17.257Z A drawing of a crystal showing a combination of the cube, octahedron and rhombic dodecahedron is shown in fig. Encyclopaedia Britannica, 11th Edition, Volume 7, Slice 7 "Crocoite" to "Cuba" 2012-01-22T03:00:24.397Z The alum there produced is the double basic potassium alum, and crystallizes into cubes instead of octahedra, i.e., the Roman alum of commerce. De Re Metallica, Translated from the First Latin Edition of 1556 2011-11-16T03:00:21.977Z A mineral relating to the zeolites, usually occurring in square prisms or octahedrons with pearly luster on the cleavage surface. Webster's Unabridged Dictionary 2012-03-24T02:00:23.513Z The cube is dual to the octahedron, the dodecahedron to the icosahedron, and the tetrahedron to itself. Justin Curry's Favorite Theorem 2017-12-09T05:00:00Z The native metal crystallizes in the cubic system, the octahedron being the commonest form, but other and complex combinations have been observed. Encyclopaedia Britannica, 11th Edition, Volume 12, Slice 2 "Gloss" to "Gordon, Charles George" 2011-10-31T02:00:28.703Z For instance, a cube would be represented merely by a square, and an octahedron by a square with lines joining the opposite corners. Encyclopaedia Britannica, 11th Edition, Volume 7, Slice 7 "Crocoite" to "Cuba" 2012-01-22T03:00:24.397Z A cube may be inscribed in an octahedron, its vertices being at the centers of the faces of the octahedron. The Teaching of Geometry 2011-10-12T02:00:52.133Z Pythagorean geometry was essentially a geometry of areas and solids; its goal was the regular solids—the tetrahedron, cube, octahedron, dodecahedron and icosahedron—which symbolized the five elements of Greek cosmology. Encyclopaedia Britannica, 11th Edition, Volume 11, Slice 6 "Geodesy" to "Geometry" 2011-09-19T02:00:10.473Z The primary crystalline form of the diamond is the octahedron, or a figure of eight sides; but it by no means confines itself to this form alone. Stories about Famous Precious Stones 2011-08-31T02:01:42.217Z Octahedra and cubes are rare, but the six-faced octahedron occurs in some of the combinations. Encyclopaedia Britannica, 11th Edition, Volume 11, Slice 4 "G" to "Gaskell, Elizabeth" 2011-08-24T02:00:20.690Z Spinel, magnetite and gold crystallize in simple octahedra. Encyclopaedia Britannica, 11th Edition, Volume 7, Slice 7 "Crocoite" to "Cuba" 2012-01-22T03:00:24.397Z Similarly, an octahedron may be inscribed in a cube, and by letting it expand a little, the faces of the cube will cut off the corners of the octahedron. The Teaching of Geometry 2011-10-12T02:00:52.133Z These give the solid angles of the tetrahedron, the octahedron and the icosahedron. Encyclopaedia Britannica, 11th Edition, Volume 11, Slice 6 "Geodesy" to "Geometry" 2011-09-19T02:00:10.473Z It is also found in the lead and copper-mines of Cornwall and S. Devon, notably near Liskeard, where fine crystals have been found, with faces of the six-faced octahedron replacing the corners of the cube. Encyclopaedia Britannica, 11th Edition, Volume 10, Slice 5 "Fleury, Claude" to "Foraker" 2011-04-03T02:00:20.883Z Gallium crystallizes in greyish-white octahedra which melt at 30.15� C. to a silvery-white liquid. Encyclopaedia Britannica, 11th Edition, Volume 11, Slice 4 "G" to "Gaskell, Elizabeth" 2011-08-24T02:00:20.690Z Combinations of the cube and octahedron are shown in figs. 6-8. Encyclopaedia Britannica, 11th Edition, Volume 7, Slice 7 "Crocoite" to "Cuba" 2012-01-22T03:00:24.397Z In particular Plato tells us that they asserted that the four elements of the real world were the tetrahedron, octahedron, icosahedron, and cube, and Plutarch ascribes this doctrine to Pythagoras himself. The Teaching of Geometry 2011-10-12T02:00:52.133Z The octahedron, with 6 vertices and 8 triangular faces; 4. Encyclopaedia Britannica, 11th Edition, Volume 11, Slice 6 "Geodesy" to "Geometry" 2011-09-19T02:00:10.473Z Fine yellow fluor-spar occurs in some of the Saxon mines, and beautiful rose-red octahedra are found in the Alps, near G�schenen. Encyclopaedia Britannica, 11th Edition, Volume 10, Slice 5 "Fleury, Claude" to "Foraker" 2011-04-03T02:00:20.883Z It is occasionally found as uneven cubes and octahedra, but more often as dendritic or earthy masses, with a blackish lead-grey colour and metallic lustre. Encyclopaedia Britannica, 11th Edition, Volume 2, Slice 5 "Arculf" to "Armour, Philip" This solid is bounded by twenty-four isosceles triangles, and may be considered as an octahedron with a low triangular pyramid on each of its faces. Encyclopaedia Britannica, 11th Edition, Volume 7, Slice 7 "Crocoite" to "Cuba" 2012-01-22T03:00:24.397Z Although Eudemus attributes all five to Pythagoras, it is certain that the tetrahedron, cube, and octahedron were known to the Egyptians, since they appear in their architectural decorations. The Teaching of Geometry 2011-10-12T02:00:52.133Z The smallest particles of fire are tetrahedra, of air octahedra, of water icosahedra. A Critical History of Greek Philosophy Fluor-spar crystallizes in the cubic system, commonly in cubes, either alone or combined with the octahedron, rhombic dodecahedron, four-faced cube, &c. Encyclopaedia Britannica, 11th Edition, Volume 10, Slice 5 "Fleury, Claude" to "Foraker" 2011-04-03T02:00:20.883Z The crystals have the form of the octahedron or rhombic dodecahedron, and are frequently twinned. Encyclopaedia Britannica, 11th Edition, Volume 2, Slice 5 "Arculf" to "Armour, Philip" Here each face of the octahedron is replaced by six scalene triangles, so that altogether there are 575 forty-eight faces. Encyclopaedia Britannica, 11th Edition, Volume 7, Slice 7 "Crocoite" to "Cuba" 2012-01-22T03:00:24.397Z It is not difficult for a class to find the relative areas of the cube and the inscribed tetrahedron and octahedron. The Teaching of Geometry 2011-10-12T02:00:52.133Z 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. Encyclopaedia Britannica, 11th Edition, Volume 5, Slice 7 "Cerargyrite" to "Charing Cross" The crystals are sometimes polysynthetic, a large octahedron, e.g., being built up of small cubes. Encyclopaedia Britannica, 11th Edition, Volume 10, Slice 5 "Fleury, Claude" to "Foraker" 2011-04-03T02:00:20.883Z They are similar to the “etched figures” produced by moistening an octahedron of alum, and have probably been produced, like them, by the action of some solvent. Encyclopaedia Britannica, 11th Edition, Volume 8, Slice 4 "Diameter" to "Dinarchus" It may be derived from the octahedron by suppressing the alternate faces. Encyclopaedia Britannica, 11th Edition, Volume 7, Slice 7 "Crocoite" to "Cuba" 2012-01-22T03:00:24.397Z The third represents a crystal formed by replacing each edge of an octahedron by a plane, it being easy to see that Euler's law still holds true. The Teaching of Geometry 2011-10-12T02:00:52.133Z The combination of these two forms produces a figure resembling an octahedron, the angle between P and P’ being 70� 7�′, corresponding to the angle 70� 32′ of the regular octahedron. Encyclopaedia Britannica, 11th Edition, Volume 7, Slice 3 "Convention" to "Copyright" Cleavage is nearly always perfect, parallel to the octahedron. Encyclopaedia Britannica, 11th Edition, Volume 10, Slice 5 "Fleury, Claude" to "Foraker" 2011-04-03T02:00:20.883Z If the grooves be left out of account, the large faces which have replaced each tetrahedron corner then make up a figure which has the aspect of a simple octahedron. Encyclopaedia Britannica, 11th Edition, Volume 8, Slice 4 "Diameter" to "Dinarchus" Six kinds of primitive forms were distinguished, namely, the cube, the regular octahedron, the regular tetrahedron, a rhombohedron, an octahedron with a rhombic base, and a double six-sided pyramid. Encyclopaedia Britannica, 11th Edition, Volume 7, Slice 7 "Crocoite" to "Cuba" 2012-01-22T03:00:24.397Z By heating a mixture of cobalt oxalate and sal-ammoniac in air, it is obtained in the form of minute hard octahedra, which are not magnetic, and are only soluble in concentrated sulphuric acid. Encyclopaedia Britannica, 11th Edition, Volume 6, Slice 5 "Clervaux" to "Cockade" On evaporating the solution dark purple octahedra of the alum are obtained. Encyclopaedia Britannica, 11th Edition, Volume 6, Slice 3 "Chitral" to "Cincinnati" 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. Encyclopaedia Britannica, 11th Edition, Volume 6, Slice 1 "Châtelet" to "Chicago" In Venus inscribe an octahedron; the sphere inscribed in it will be Mercury’s.’ The Astronomy of Milton's 'Paradise Lost' An axis of symmetry of another kind is that which passing through the centre O is normal to a face of the octahedron. Encyclopaedia Britannica, 11th Edition, Volume 7, Slice 7 "Crocoite" to "Cuba" 2012-01-22T03:00:24.397Z It crystallizes in red octahedra and dyes silk and wool yellow. Encyclopaedia Britannica, 11th Edition, Volume 3, Part 1, Slice 1 "Austria, Lower" to "Bacon" It forms red octahedra and is less soluble in water than the corresponding potassium compound. Encyclopaedia Britannica, 11th Edition, Volume 6, Slice 3 "Chitral" to "Cincinnati" It is the only metal of a yellow color; it is readily crystallizable, and always assumes one or more of the symmetrical shapes, such as the cube or regular octahedron. The Continental Monthly, Vol 3 No 3, March 1863 Devoted To Literature And National Policy The stone, a clear yellow octahedron of about ten carats' weight, was passed from hand to hand to be admired and appraised. Reminiscences of a South African Pioneer There being six pairs of parallel edges on an octahedron, there are consequently six dyad axes of symmetry. Encyclopaedia Britannica, 11th Edition, Volume 7, Slice 7 "Crocoite" to "Cuba" 2012-01-22T03:00:24.397Z It was in the form of an obtuse octahedron, and on one side was quite smooth and transparent. The Privateersman It crystallizes in regular octahedra, but is usually found as grains or as granular to compact masses. Encyclopaedia Britannica, 11th Edition, Volume 6, Slice 3 "Chitral" to "Cincinnati" They all crystallize in octahedra and contain twelve molecules of water of crystallization. An Elementary Study of Chemistry One would cut a piece of alum into the ordinary octahedron form and scrape it so as to round off the edges. Reminiscences of a South African Pioneer Examples of simple forms amongst crystallized substances are octahedra of alum and spinel and cubes of salt and fluorspar. Encyclopaedia Britannica, 11th Edition, Volume 7, Slice 7 "Crocoite" to "Cuba" 2012-01-22T03:00:24.397Z If a little more ammonia is added, several varieties of rhombic octahedra appear; if a little nitric acid is added, the rectangular prism appears again. On the Genesis of Species The form is a cube modified to an octahedron and a rhombic dodecahedron. To The Gold Coast for Gold, Vol. II A Personal Narrative Look here," said the professor to his colleague, "I have been watching that fly on the octahedron, and it confines its walks entirely to the edges. Amusements in Mathematics Two of these generate the cube and the octahedron; five of these generate the dodecahedron and the icosahedron. Occult Chemistry Clairvoyant Observations on the Chemical Elements Two misshapen or distorted octahedra are represented in figs. Encyclopaedia Britannica, 11th Edition, Volume 7, Slice 7 "Crocoite" to "Cuba" 2012-01-22T03:00:24.397Z Gold crystallizes in cubes and octahedrons, is of a beautiful yellow color, great lustre, and is the most malleable and ductile of all the metals. A System of Instruction in the Practical Use of the Blowpipe Being A Graduated Course Of Analysis For The Use Of Students And All Those Engaged In The Examination Of Metallic Combinations It is the only metal of a yellow color; it is easily chrystallizable, and always assumes one or more of the symmetrical shapes,—such as the cube or octahedron. The Bay State Monthly — Volume 2, No. 6, March, 1885 I will just explain that the octahedron is one of the five regular, or Platonic, bodies, and is contained under eight equal and equilateral triangles. Amusements in Mathematics We have again the funnel with its ovoids, but now there are eight funnels opening on the eight faces of the octahedron. Occult Chemistry Clairvoyant Observations on the Chemical Elements Native gold is found crystallised in the forms of the octahedron, the cube, and the dodecahedron, of which the cube is considered as the primary form. Punch, or the London Charivari, Volume 100, March 7, 1891 It has a fibrous structure, crystallizes easily in regular octahedrons, presenting often the peculiar arborescent appearance of the fern. A System of Instruction in the Practical Use of the Blowpipe Being A Graduated Course Of Analysis For The Use Of Students And All Those Engaged In The Examination Of Metallic Combinations It is the correlative of the octahedron of three-dimensional space. Architecture and Democracy Though we cannot really see all the sides of the octahedron at once, we can make a projection of it that suits our purpose just as well. Amusements in Mathematics It is worthy of notice that in diatomic elements four funnels open on the faces of tetrahedra; in triatomic, six funnels on the faces of cubes; in tetratomic, eight funnels on the faces of octahedra. Occult Chemistry Clairvoyant Observations on the Chemical Elements Now, inscribe in the earth an icosahedron, the sphere inscribed in it will be Venus: inscribe an octahedron in Venus: the circle inscribed in it will be Mercury.” Kepler These crystals appear to be regular octahedrons when observed under the microscope. A System of Instruction in the Practical Use of the Blowpipe Being A Graduated Course Of Analysis For The Use Of Students And All Those Engaged In The Examination Of Metallic Combinations Suppose, for example, that we attempt to deal decoratively which such simple figures as the three lowest Platonic solids—the tetrahedron, the hexahedron, and the octahedron. Architecture and Democracy In the diagram the six points represent the six angles of the octahedron, and four lines proceed from every point under exactly the same conditions as the twelve edges of the solid. Amusements in Mathematics The members of the group are all tetrads, and have eight funnels, opening on the eight faces of the octahedron. Occult Chemistry Clairvoyant Observations on the Chemical Elements It will not be hard to draw a cube or an octahedron in this way; indeed, the first stereoscopic figures were pairs of outlines, right and left, of solid bodies, thus drawn. The Atlantic Monthly, Volume 03, No. 20, June, 1859 In the metallic state, copper is of a red color, has great lustre and tenacity, is ductile and malleable, and crystallizes in octahedrons and cubes. A System of Instruction in the Practical Use of the Blowpipe Being A Graduated Course Of Analysis For The Use Of Students And All Those Engaged In The Examination Of Metallic Combinations Sulphur can be obtained in two crystalline modifications, in orthorhombic octahedra, or in monoclinic prisms, the former of which is the more stable at ordinary temperatures. The Gutenberg Webster's Unabridged Dictionary Section S In its pure crystallized state it constitutes the diamond, the hardest of known substances, occuring in monometric crystals like the octahedron, etc. The Gutenberg Webster's Unabridged Dictionary Section C Carbon is the typical octahedron, and a clear understanding of this will enable us to follow easily the constitution and disintegration of the various members of these groups. Occult Chemistry Clairvoyant Observations on the Chemical Elements Such ore is found in rich grey masses, yielding a black dust crystallized in regular octahedrons, highly magnetic, and in Europe the best quality of iron is made from it. The Mysterious Island It is found frequently crystallized in octahedrons in Scandinavia and other places. A System of Instruction in the Practical Use of the Blowpipe Being A Graduated Course Of Analysis For The Use Of Students And All Those Engaged In The Examination Of Metallic Combinations Platonic bodies; cube, rhomboid; tetrahedron, pentahedron, hexahedron, octahedron, dodecahedron, icosahedron, eicosahedron; prism, pyramid; parallelopiped; curb roof, gambrel roof, mansard roof. Roget's Thesaurus of English Words and Phrases The second solid is composed of the same triangles, which unite as eight equilateral triangles, and make one solid angle out of four plane angles—six of these angles form a regular octahedron. Timaeus It was the oxydulous iron, which is found in confused masses of a deep gray color; it gives a black dust, crystallized in the form of the regular octahedron. The Mysterious Island According to Plato earth was composed of cubes, fire of regular pyramids, air of regular octahedrons, water of regular icosahedrons. Timaeus It crystallizes in cubes and octahedrons; is of a pure white color, great lustre, is very malleable and ductile, and is softer than copper, but harder than gold. A System of Instruction in the Practical Use of the Blowpipe Being A Graduated Course Of Analysis For The Use Of Students And All Those Engaged In The Examination Of Metallic Combinations |
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