X-ray photoemission study of orthorhombic selenium; a new allotrope
of crystalline selenium.
Similarly, a comparison of the Raman spectra of two carbon allotropes
, diamond and graphite, easily distinguishes the two materials even though both are composed entirely of C-C bonds.
EPA considers substances to have different molecular identities when they have different molecular formulas; have the same molecular formulas, but have different atom connectivities; have the same molecular formulas and atom connectivities, but have different spatial arrangements of atoms; have the same type of atoms, but have different crystal lattices, (26) are different allotropes
(27) of the same element, or have different isotopes (28) of the same elements.
As a chemical term, allotropic means "having different physical properties, though unchanged in substance" (OED), such as diamonds and coal both being allotropes
They identified and measured subatomic particles and radiation, rejected "plum pudding" atoms, imagined "liquid-drop" nuclei, quantified isotopes and allotropes
, and finally, in the late 1930s, came to understand that splitting atoms to release enormous energy was not only theoretically possible, but technically feasible.
Curiously, ironically, it is deeply bound up with that unmodulated craving for perfection that often goes under the name of idealism but really is one of the more destructive allotropes
One can also probe physical properties, including molecular orientation, degree of crystallinity, polymorphs or allotropes
, crystal and domain size, crystal defects, and stress/strain.
The ropes might well be the allotropes
of puppet strings, even if the dependent manikins in Two Standing Nudes and The Strange Man are stringless.
But allotropy is a property special to (dependent on) allotropes
and should appear only under allotropes
Carbon in all its many forms--diamonds, graphite, fullerenes, coal, and other allotropes
, including solid, liquid, gaseous, and plasma forms--may join silicon as a key and virtually inexhaustible resource.
As a space-saving measure the figural complex in question will sometimes be referred to as a tropeme, and the three individual figures as allotropes
without, however, any attempt being made to press exaggerated claims for conceptual originality or universal applicability.
Diamond and graphite, the only other known allotropes
of carbon, require temperatures on the order of 3000 [degrees] C (5400 [degrees] F) to evaporate.