7789-09-5
Ammonium dichromate
CAS: 7789-09-5
Molecular Formula: Cr2H8N2O7
7789-09-5 - Names and Identifiers
| Name | Ammonium dichromate |
| Synonyms | AMMONIUM BICHROMATE Ammonium dichromate AMMONIUM DICHROMATE diammoniumdichromate AMMONIUM PYROCHROMATE Ammonium dichromate (VI) Dichromicaciddiammoniumsalt dichromicacid,diammoniumsalt Dichromic acid, diammonium salt chromicacid[h2cr2o7],diammoniumsalt dichromicacid[h2cr2o7],diammoniumsalt Chromic acid (H2Cr2O7), diammonium salt diammonium oxido-(oxido-dioxo-chromio)oxy-dioxo-chromium |
| CAS | 7789-09-5 |
| EINECS | 232-143-1 |
| InChI | InChI=1/2Cr.2H3N.7O/h;;2*1H3;;;;;;;/q;;;;;;;;;2*-1/p+2/rCr2O7.2H3N/c3-1(4,5)9-2(6,7)8;;/h;2*1H3/q-2;;/p+2 |
7789-09-5 - Physico-chemical Properties
| Molecular Formula | Cr2H8N2O7 |
| Molar Mass | 252.06 |
| Density | 2.150 |
| Melting Point | 170°C (dec.)(lit.) |
| Water Solubility | 360 g/L (20 ºC) |
| Solubility | H2O: 1M at20°C, clear, colorless |
| Vapor Density | 8.7 (vs air) |
| Appearance | Solid |
| Color | Orange to red |
| Odor | Odorless |
| Exposure Limit | ACGIH: TWA 0.0002 mg/m3; STEL 0.0005 mg/m3 (Skin)OSHA: Ceiling 0.1 mg/m3NIOSH: IDLH 15 mg/m3; TWA 0.0002 mg/m3 |
| Merck | 14,515 |
| Stability | Stability Strong oxidizer - contact with flammable materials may cause fire. Reactions carried out in closed vessels may lead to explosion. Incompatible with organic materials, strong reducing agents. |
| Physical and Chemical Properties | Trait orange-red monoclinic crystal. relative density 2.15(25 ℃) soluble in water and ethanol, insoluble in acetone. |
| Use | Used for printing and dyeing, alizarin synthesis, chrome alum manufacturing, petroleum refining, tanning, spices, photographic medicine, pyrotechnic, ceramics, etc |
7789-09-5 - Risk and Safety
| Risk Codes | R45 - May cause cancer R46 - May cause heritable genetic damage R60 - May impair fertility R61 - May cause harm to the unborn child R2 - Risk of explosion by shock, friction, fire or other sources of ignition R8 - Contact with combustible material may cause fire R21 - Harmful in contact with skin R25 - Toxic if swallowed R26 - Very Toxic by inhalation R34 - Causes burns R42/43 - May cause sensitization by inhalation and skin contact. R48/23 - R50/53 - Very toxic to aquatic organisms, may cause long-term adverse effects in the aquatic environment. |
| Safety Description | S53 - Avoid exposure - obtain special instructions before use. S45 - In case of accident or if you feel unwell, seek medical advice immediately (show the label whenever possible.) S60 - This material and its container must be disposed of as hazardous waste. S61 - Avoid release to the environment. Refer to special instructions / safety data sheets. |
| UN IDs | UN 1439 5.1/PG 2 |
| WGK Germany | 3 |
| RTECS | HX7650000 |
| TSCA | Yes |
| HS Code | 28415000 |
| Hazard Class | 5.1 |
| Packing Group | II |
| Toxicity | LDLo scu-gpg: 25 mg/kg EQSSDX 1,1,75 |
7789-09-5 - Upstream Downstream Industry
| Raw Materials | Ammonium chloride Sodium Dichromate |
7789-09-5 - Nature
Open Data Verified Data
orange-red crystals. Tasteless. No hygroscopicity. d: 155. 180 degrees C decomposition. Soluble in water, solubility in water (W/W):15. 16% (0 °c);26.67%( 20 °c), 36.99% (40 °c); 46.14%( 60 °c); 54. 20% (80 degrees C); 60. 89%(100 degrees C). Soluble in ethanol, insoluble in acetone. Strong oxidation. Mixing with reducing agents, organics, combustible materials such as sulfur, phosphorus, or metal powders, etc., can form explosive mixtures that can cause combustion or explosion by friction, shock, or impact.
Last Update：2024-01-02 23:10:35
7789-09-5 - Preparation Method
Open Data Verified Data
chromium trioxide was dissolved in water. After clarification, the clear solution was poured and cooled to 8-10 °c. With constant stirring, ammonia was added in small portions until the solution was neutral and maintained below 15 °c. When the solution is cooled to 10 °c, there is crystallization, which is filtered by suction, washed with 10 ~ 15mL ice water, and dried at 50 °c to obtain pure ammonium dichromate.
Last Update：2022-01-01 09:00:23
7789-09-5 - Use
Open Data Verified Data
analytical reagent for the detection of barium. It is also used in mordant, perfume synthesis, photographic plate making, printing and dyeing, chrome alum manufacturing, petroleum refining, tanning, pyrotechnic, ceramics and so on.
Last Update：2022-01-01 09:00:24
7789-09-5 - Safety
Open Data Verified Data
inhalation of ammonium dichromate powder can cause inflammation of respiratory organs and nasal cavities. When ammonium dichromate spatters into the skin, eyes, immediately rinse with water, severe cases should be immediately sent to the hospital for treatment. The maximum allowable concentration of chromate, dichromate (as Cr03) is 0.01 mg/m3. Production workers should be protected. Keep away from the heat source. It cannot be co-stored with organic matter, flammable materials and acids. Irritation is strongly irritating to the skin. There is sufficient evidence of carcinogenicity in humans. This substance may be harmful to the environment, and special attention should be paid to the water body.
Last Update：2022-01-01 09:00:24
7789-09-5 - Reference Information
| pH range | 3 - 4 |
| Decomposition | 170 °C |
| EPA chemical substance information | information provided by: ofmpeb.epa.gov (external link) |
| solubility in water (g/100ml) | grams dissolved per 100ml of water at different temperatures (℃): 18.2g/0 ℃;25.5g/10 ℃;35.6g/20 ℃;46.5g/30 ℃;58.5g/40 ℃ 86g/60 ℃;115g/80 ℃;156g/100 ℃ |
| toxicity | inhalation of ammonium dichromate powder causes inflammation of respiratory organs and nasal cavities. Serious can cause septal cartilage perforation, so that respiratory organ damage, and even cause lung sclerosis. When ammonium dichromate was spattered onto the skin, it was immediately rinsed with water for 15min. When eczema and dermatitis appear, the local use of lotion, dusting powder, no irritation of the ointment. If you accidentally fall into the eyes, immediately rinse with water for more than 15min, drip into Cod Liver Oil, then drip into the 30% sulfanilamide acetyl solution. Severe cases should be immediately sent to the hospital for treatment. The maximum allowable concentration of chromate and dichromate (based on CrO3) is 0.01 mg/m3. The production equipment should be completely sealed, and the work place should be well ventilated to keep the concentration of chromium in the air very low. Production workers should wear work clothes, masks, latex gloves and other labor protection articles, and wear gas masks when there is aerosol in the air. |
| Use | used in gravure printing of photographic plate making, the preparation of developer, the manufacture of ceramic glaze, pyrotechnic, synthetic spices, printing and dyeing mordant, plastic and rubber foaming agent, etc. used as analytical reagents, mordant, but also for the synthesis of spices mainly used in gravure printing photographic plate making, the preparation of developer and lithographic development. For the manufacture of ceramic glaze, pyrotechnic. It is a raw material for the production of pure nitrogen and sodium dodecyl sulfate. For the synthesis of spices, coconut oil as raw material for the preparation of ten diol, ten four alcohol as a catalyst. It is used as a mordant for acid dyes and mordant dyes in the printing and dyeing industry. It is also used as a blowing agent for plastics and rubber. used in printing and dyeing, alizarin synthesis, chrome alum manufacturing, petroleum refining, tanning, spices, photographic medicine, pyrotechnic, ceramics and so on |
| production method | industrial production methods include double decomposition method and neutralization method. In the double decomposition method, sodium dichromate and ammonium chloride are dissolved in a mixture of ammonium dichromate mother liquor and washing liquid according to a theoretical ratio, and heated to boiling so that the concentration of the reaction solution reaches 37 to 38 Bé. After clarification and separation of insoluble matter, cooled to normal temperature. Ammonium dichromate crystals were precipitated, the crystals and the mother liquor were separated by filtration, and then washed with water to remove chloride. After centrifugal dehydration and drying, the ammonium dichromate product was prepared. Na2Cr2O7 2NH4Cl →(NH4)2Cr2O7 2NaCl |
| category | oxidant |
| toxicity grade | high toxicity |
| Acute toxicity | subcutaneous-guinea pig LDL0: 25 mg/kg |
| explosive hazard characteristics | unstable oxidant; Mixed with reductant, sulfur, phosphorus, etc, friction can burst |
| flammability hazard characteristics | relatively flammable; Toxic chromium compounds generated by thermal decomposition, nitrogen oxides and ammonia gas |
| storage and transportation characteristics | The warehouse is ventilated and dried at low temperature; It is light and easy to discharge; It is combined with organic matter, reductant, sulfur and phosphorus combustible substances, separate storage of food raw materials |
| fire extinguishing agent | water and sand mist |
| Occupational Standard | TWA 0.05 mg (chromium)/m3 |
| spontaneous combustion temperature | 218°C |
| toxic substance data | information provided by: pubchem.ncbi.nlm.nih.gov (external link) |
Last Update：2024-04-10 22:29:15
