Barnhart J
American Chrome & Chemicals, Corpus Christi, Texas 78469, USA.
Regul Toxicol Pharmacol. 1997 Aug;26(1 Pt 2):S3-7. doi: 10.1006/rtph.1997.1132.
Chromium is the 21st most abundant element in the Earth's crust with a mean concentration in United States soils of about 40 mg/kg. Although it exists in several oxidation states, the zero, trivalent, and hexavalent states are the most important in commercial products and the environment. Nearly all naturally occurring chromium is in the trivalent state, usually in combination with iron or other metal oxides. Although only about 15% of the chromium mined is used in the manufacture of chemicals, most applications of chromium utilize the chemistry of chromium. For instance, the "stainless" nature of stainless steel is due to the chemical properties of the chromium oxides which form on the surface of the alloy. Similarly, the protective properties of chrome plating of metals, chromated copper arsenate (CCA) treatment of wood, and chrome tanning of leather are all dependent on chromium chemistry. The key to these uses is that under typical environmental and biological conditions of pH and oxidation-reduction potential, the most stable form of chromium is the trivalent oxide. This form has very low solubility and low reactivity resulting in low mobility in the environment and low toxicity in living organisms. In this paper the chemical properties of chromium are discussed for the major commercial products in the context of the Eh-pH diagram for chromium.
铬是地壳中第21丰富的元素，在美国土壤中的平均浓度约为40毫克/千克。尽管它以几种氧化态存在，但零价、三价和六价态在商业产品和环境中最为重要。几乎所有天然存在的铬都处于三价态，通常与铁或其他金属氧化物结合。虽然开采的铬只有约15%用于制造化学品，但铬的大多数应用都利用了铬的化学性质。例如，不锈钢的“不锈”特性归因于在合金表面形成的铬氧化物的化学性质。同样，金属镀铬的保护性能、木材的铬酸铜砷酸盐（CCA）处理以及皮革的铬鞣制都依赖于铬化学。这些用途的关键在于，在典型的环境和生物条件下的pH值和氧化还原电位下，铬最稳定的形式是三价氧化物。这种形式的溶解度很低且反应性低，导致在环境中的迁移率低，对生物体的毒性也低。本文在铬的Eh-pH图的背景下，讨论了铬在主要商业产品中的化学性质。
