Хромат калия

Химические свойства

lemon-yellow crystals

Использование

Potassium chromate (K2CrO4) is soluble in water and is used to make bright yellow inks and paint pigments. It is also used as a reagent in chemical laboratories and as a mordant to “fix” dyes in colored textiles.

Определение

ChEBI: A potassium salt consisting of potassium and chromate ions in a 2:1 ratio.

Общее описание

Potassium chromate is a yellow crystalline solid. Potassium chromate is soluble in water. The primary hazard is the threat to the environment. Immediate steps should be taken to limit its spread to the environment. Potassium chromate is used in chemical analysis, in making pigments for paints and inks, as a fungicide, and to make other chromium compounds.

Реакции воздуха и воды

Soluble in water.

Профиль реактивности

Oxidizing agents, such as Potassium chromate , can react with reducing agents to generate heat and products that may be gaseous (causing pressurization of closed containers). The products may themselves be capable of further reactions (such as combustion in the air). The chemical reduction of materials in this group can be rapid or even explosive, but often requires initiation (heat, spark, catalyst, addition of a solvent). Explosive mixtures of inorganic oxidizing agents with reducing agents often persist unchanged for long periods if initiation is prevented. Such systems are typically mixtures of solids, but may involve any combination of physical states. Some inorganic oxidizing agents are salts of metals that are soluble in water; dissolution dilutes but does not nullify the oxidizing power of such materials. Organic compounds, in general, have some reducing power and can in principle react with compounds in this class. Actual reactivity varies greatly with the identity of the organic compound. Inorganic oxidizing agents can react violently with active metals, cyanides, esters, and thiocyanates.

Опасность

Toxic by ingestion and inhalation.

Угроза здоровью

Inhalation causes local irritation of mucous membranes; continuing nose irritation can result in perforation of nasal septum. Ingestion may cause violent gastroenteritis, circulatory collapse, vertigo, coma, and toxic nephritis; ingestion of excessive quantities can be fatal. Contact with eyes causes severe irritation and conjunctivitis. Repeated or prolonged exposure to dust, mist, or solutions may cause dermatitis; contact with breaks in the skin may cause ``chrome sores'' appearing as slow-healing, hard-rimmed ulcers which leave the area vulnerable to infection.

Пожароопасность

Behavior in Fire: May increase intensity of fire if in contact with combustible materials. Cool containers and spilled material with plenty of water.

Профиль безопасности

Confirmed carcinogen with experimental tumorigenic data. Poison by ingestion, intravenous, subcutaneous, and intramuscular routes. An experimental teratogen. Other experimental reproductive effects. Human mutation data reported. A powerful oxidizer. When heated to decomposition it emits toxic fumes of K2O. Used as a mordant for wool, in the oxidizing and treatment of dyes on materials. See also CHROMIUM COMPOUNDS.

Возможный контакт

Potassium chromate is used in printing: photomechanical processing; chrome-pigment production; and wool preservative methods; to make dyes, pigments, inks and enamels; as an oxidizing agent; analytical reagent; in electroplating; explosives.

Перевозки

UN1479 Oxidizing solid, n.o.s., Hazard Class: 5.1; Labels: 5.1-Oxidizer, Technical Name Required. UN3288 Toxic solids, inorganic, n.o.s., Hazard Class: 6.1; Labels: 6.1-Poisonous materials, Technical Name Required

Методы очистки

Crystallise it from conductivity water (0.6g/mL at 20o), and dry it between 135o and 170o.

Несовместимости

A powerful oxidizer. Violent reactions with combustibles, organics, powdered metals; or easily oxidizable substances. Contact with hydroxylamine, hydrazine causes explosion.