Search the Dictionary

A rare metallic element of the platinum group, found native as an alloy in platinum ore, and in iridosmine. It is a hard, infusible, bluish or grayish white metal, and the heaviest substance known. Its tetroxide is used in histological experiments to stain tissues. Symbol Os. Atomic weight 191.1. Specific gravity 22.47…

The native compound of iridium and osmium. It is found in flattened metallic grains of extreme hardness, and is often used for pointing gold pens.

but harder, and brittle, and indifferent to most corrosive agents. With the exception of osmium, it is the heaviest substance known, its specific gravity being 22.4. Symbol Ir. Atomic weight 192.5.

A rare sulphide of osmium and ruthenium found with platinum in Borneo and Oregon.

Of, pertaining to, or designating, a nitrogenous acid of osmium, H2N2Os2O5, forming a well-known series of yellow salts.

Pertaining to, derived from, or containing, osmium; specifically, designating those compounds in which it has a valence higher than in other lower compounds; as, osmic oxide. Osmic acid. (Chem.) (a) Osmic tetroxide. [Obs.] (b) Osmic acid proper, an acid analogous to sulphuric acid, not known in the free state, but form…

Denoting those compounds of osmium in which the element has a valence relatively lower than in the osmic compounds; as, osmious chloride. [Written also osmous.] Osmious acid (Chem.), an acid derived from osmium, analogous to sulphurous acid, and forming unstable salts. It is a brown amorphous substance.…

and palladium, whose specific gravities are about 12; and the heavy platinum group, viz., osmium, iridium, and platinum, whose specific gravities are over 21. -- Platinum sponge (Chem.), metallic platinum in a gray, porous, spongy form, obtained by reducing the double chloride of platinum and ammonium. It absorbs oxyg…

An oxide having four atoms of oxygen in the molecule; a quadroxide; as, osmium tetroxide, OsO.