Хром (II) хлорид

Химические свойства

grey green powder

Использование

Chromium(II) chloride is used as a precursor to other inorganic and organometallic chromium complexes. It is a reagent in the Nozaki-Hiyama-Kishi reaction. It is also used in the Takai olefination to prepare vinyl iodides from aldehydes in the presence of iodoform.

Общее описание

A white crystalline solid. The primary hazard is the threat to the environment. Immediate steps must be taken to prevent its spread to the environment. CHROMIUM(II) CHLORIDE is used to make other chemicals and as an oxygen absorbent.

Реакции воздуха и воды

Stable in dry air, but oxidizes rapidly in moist air or standing water with liberation of Hydrogen, [Merck, 11th ed., 1989]. Soluble in water.

Профиль реактивности

Inorganic reducing agents, such as CHROMIUM(II) CHLORIDE, react with oxidizing agents to generate heat and products that may be flammable, combustible, or otherwise reactive. Their reactions with oxidizing agents may be violent. Long storage of a CHROMIUM(II) CHLORIDE solution culminated in an explosion. This was ascribed to the slow buildup of hydrogen gas that was produced by reduction of water by the Cr(II) ion [MCA Case History No. 1660].

Угроза здоровью

DUST: Harmful if inhaled. SOLID: Irritating to skin and eyes. Harmful if swallowed.

Возможный контакт

It is used in metal alloys and metal finishing; textile treatment including mothproofing, waterproofing, printing; and dying, leather tanning; making photographic chemicals; and green pigments for various uses.

Перевозки

UN3260 Corrosive solid, acidic, inorganic, n.o. s., Hazard class: 8; Labels: 8-Corrosive material, Technical Name Required.

Методы очистки

It is obtained from the dihydrate by heating in vacuo at 180o. It is a very hygroscopic white powder which dissolves in H2O to give a sky blue solution. It is stable in dry air but oxidises rapidly in moist air and should be stored in air tight containers. It sublimes at 800o in a current of HCl gas and should be cooled in the presence of HCl gas. Alternatively it can be washed with air-free Et2O and dried at 110-120o. [Burg Inorg Synth III 150 1950, Balthis & Bailar (4 H2O) Inorg Synth I 125 1939, Hein & Herzog in Handbook of Preparative Inorganic Chemistry (Ed. Brauer) Academic Press Vol II pp 1336-1338 1965.]

Несовместимости

Very hygroscopic. The substance is a strong reducing agent. Reacts with oxidizers. Reacts with water, forming flammable hydrogen gas