Bichromate of potash

Synonyms Bichromate of potash, Bichromate of potassa, Potassium dichromate, Red chromate of potash, Red chromate of potassa. 

SYNS BICHROMATE OF POTASH CHROMIC ACID, DIPOTASSIUM SALT DIPOTASSIUM DICHROMATE lOPEZITE KALIUMDICHROMAT (GERMAN) POTASSIUM DICHROMATE(VI)... 

BICHROMATE de SODIUM (French) (10588-01-9) see sodium dichromate. BICHROMATE of POTASH (7778-50-9) see potassium bichromate. 

BICHROMATE of POTASH (7778-50-9). Noncombustible, but many chemical reactions can cause fire and explosions. A powerful oxidizer. Violent reaction with many substances, including combustible materials, reducing agents, organic materials, finely divided metals, ammonium nitrate, ammonium perchlorate, fluorine, hydrazine, hydrazinium nitrate, hydrox-ylamine, iron powder, nitric acid, potassium iodide, sodium borohydride, sodium bromide, sodium tetraborate and its decahydrate, tungsten and zirconium dusts. Mixture with sulfuric acid forms chromic acid. Incompatible with ethylene glycol, iron, tungsten. 

The sulphate of protoxide of manganese, Mn 0, s6, remains in the retort. This process is trouhlesome, and the retort is generally broken dnring cooling. A better process, lately proposed, is to heat bichromate of potash with an excess of sulphuric acid. 

This oxide may be obtained by heating to redness the bichromate of potash, K0,2Cr03, when neutr chromate, KO,CrO, is formed, sesquioxide is produced, 07,0, and oxygen is disengaged. 2(K0,2Cr03)=2(K0,Cr0,)-l-Cr303+03. The... 

Prepared by adding 1 vol. of a cold saturated solution of bichromate of potash to IJ vol. of pure oil of vitriol, and allowing the mixture to cool in a covered capsule, or in a flask, when it deposits beautiful deep red needles of chromic acid. The liquid being drained off, these are laid on a porous brick to diy, covered with a bell jar. They must be preserved in very tightly-stoppered bottles, as they are highly deliquescent. 

Bichromate of potash, KO, 2 Cr O3, is much used in calicor g, and is obtained by fusing chrome iron ore with nitre. 

Chromate of lead, PbO, CrOs, is an insoluble powder, of a very fine yellow colour, much used in painting, under the name of chrome yellow. It is formed by the action of soluble salts of lead on chromate, or bichromate of potash. 

Bichloroethane. See Ethylene dichloride Bichromate of potash. See Potassium dichromate... 

Synonyms Bichromate of potash Chromic acid, dipotassium salt Dipotassium dichromate Potassium bichromate Potassium dichromate (VI)... 

Synonyms dichromic acid dipotassium salt bichromate of potash potassium dichromate (VI) dipotassium dichromate iopezite ... 

Happily a non-poisonous though less effective serpent can be made by using bichromate of potash 2 parts nitrate of potash, 1 part powdered sugai , 1 part. Tliese ingredients must be powdered separately and then thoroughly mixed. Small paper cones are made about the size of a pastile and the mixture pressed into them. 

On this principle, beautiful crystal baskets, ornaments, etc., can be built of alum, sulphate of copper, and bichromate of potash. The baskets are made of covered copper wire, and when the salts crystallize on them as a nucleus or centre, they are constantly removed to fresh solutions, in which they must be completely covered, until red, white, and blue sparkling crystal structures are formed. They wUl retain their brilliancy for an indefinite period by being put under a glass shade in which is placed a cup containing a little water. 

The term is generally used to refer to Prussian blue precipitated onto a barium sulfate, baryte (qq.v.) or similar base. Davidson (1880) says of Brunswick, Celestial and damp blues Brunswick or Celestial Blue is made by precipitating the alumine from a solution of alum by carbonate of soda, washing the precipitate, and adding sulphate of baryta, sulphate of iron, yellow prussiate of potash, and some bichromate of potash. When dried, this mixture is known as Brunswick or celestial blue but when the sulphate of baryta is left out, and the material is not dried, it is called damp blue. Heaton (1928) lists Bnmswick blue as a current synonym, a reduced Prussian blue . Mayer (1991) also indicates that it may contain some ultramarine blue (. v.). 

Salter (1869) describes a pigment he calls citrine brown, produced, he states, From boiling, hot, or cold solutions of bichromate of potash and hyqxrsulphite of soda in excess. .. it is a hydrated oxide of chronuum. It had not, apparently, been introduced as a commercial pigment. 

Salter (1869) states that ThaUiinn orange is produced when bichromate of potash is added to a neutral salt of the protoxide of thallium, as an orange-yellow precipitate. It was clearly a speculative and unproven pigment as far as the author was concerned the composition is likely to have been a thaUium chromate q.v.). 

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