platinum

(plat’in-um) [L.]._ A heavy, soft, whitish metal, resembling tin: symbol, Pt; atomic weight, 194.3; specific gravity, 21.5. It also occurs as a black powder (p. dlack) and as a spongy substance (spongy p.). Metallic platinum is insoluble except in nitro hydrochloric acid, and is fusible only at very high temperatures; it is therefore used in the manufacture of chemic apparatus. Platinum black and spongy platinum’ have a strong affinity for oxygen, and act as powerful oxidizing agents. p. chlorid, platinic tetra chlorid, a poisonous substance, used as a chemic reagent and in syphilis. Dose, 4-4 gr. (0.008-0.033 gm.).