Tham khảo tài liệu 'materials handbook 15th ed - g. brady_ h. clauser_ j. vaccari (mcgraw-hill_ 2002) episode 2', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 80 ARSENIC pharmaceuticals in effervescent beverages and as a mordant in dyeing. The pods of the tamarind tree Tamarindus indica of India contain 12 tartaric acid and 30 sugars. They are used in medicine and for beverages under the name of tamarind. Rochelle salts is potassium sodium tartrate KNa C4H4O6 4H2O a colorless to bluish-white crystalline solid of specific gravity and melting point 167 F 75 C which is soluble in water and in alcohol. It is used in medicines and in silvering mirrors. Like quartz it is doubly refractive and is used in piezoelectric devices where water solubility is not a disadvantage. ARSENIC. A soft brittle poisonous element of steel-gray color and metallic luster symbol As. The melting point is 1562 F 850 C and specific gravity is . In atomic structure it is a semimetal lacking plasticity and is used only in alloys and in compounds. When heated in air it burns to arsenious anhydride with white odorous fumes. The bulk of the arsenic used is employed in insecticides rat poisons and weed killers but it has many industrial uses especially in pigments. It is also used in poison gases for chemical warfare. The white poisonous powder commonly called arsenic is arsenic trioxide or arsenious oxide As2O3 also known as white arsenic. When marketed commercially it is colored pink to designate it as a poison. White arsenic is marketed as Refined 99 pure High-grade 95 to 99 and Low-grade -95 . Refined arsenic trioxide is used as a decolorizer and fining agent in the production of glass and for the production of arsenic compounds. Monosodium methylarsonate disodium methylarsonate and methane arsenic acid also called cacodylic acid are used for weed control. Arsenic is added to anti-monial lead alloys and white bearing metals for hardening and to increase fluidity and to copper to increase the annealing temperature for such uses as radiators. It is also used in lead shot to diminish cohesion and small amounts are used as negative electron carriers
