Chromic acid (H2CrO4), diammonium salt
Ammonium chromate
CAS: 7788-98-9
Molecular Formula: CrH8N2O4
Chromic acid (H2CrO4), diammonium salt - Names and Identifiers
| Name | Ammonium chromate |
| Synonyms | HSDB 482 Ammonium chromate Ammonium chronate AMMONIUM CHROMATE diammoniumchromate Diammonium chromate ammoniumchromate(vi) Ammonium chromate(VI) neutralammoniumchromate Neutral ammonium chromate Chromic acid, diammonium salt diammonium dioxido(dioxo)chromium chromicacid[h2cro4],diammoniumsalt chromicacid(h2cro4),diammoniumsalt Chromic acid (H2CrO4), diammonium salt Ammonium chromate [Chromium and chromium compounds] |
| CAS | 7788-98-9 |
| EINECS | 232-138-4 |
| InChI | InChI=1/Cr.2H3N.4O/h;2*1H3;;;;/q;;;;;2*-1/p+2/rCrO4.2H3N/c2-1(3,4)5;;/h;2*1H3/q-2;;/p+2 |
Chromic acid (H2CrO4), diammonium salt - Physico-chemical Properties
| Molecular Formula | CrH8N2O4 |
| Molar Mass | 152.07 |
| Density | 1.91 g/mL at 25 °C (lit.) |
| Melting Point | 180°C (dec.) |
| Water Solubility | Soluble in water. Slightly soluble in liquid ammonia, acetone, methanol. Insoluble in ethanol. |
| Solubility | H2O: 1M at20°C, clear, yellow |
| Appearance | Crystalline |
| Specific Gravity | 1.91 |
| Color | Yellow-orange |
| 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 | 14,510 |
| Physical and Chemical Properties | Yellow monoclinic crystal. Relative density d121.91. Decomposition was initiated by heating to 180 °c. Soluble in cold water, slightly soluble in ammonia, acetone, insoluble in alcohol. Long-term storage can be decomposed to release ammonia, partial conversion to ammonium dichromate. |
| Use | Used as analytical reagents, oxidants and mordant |
Chromic acid (H2CrO4), diammonium salt - Risk and Safety
| Risk Codes | R49 - May cause cancer by inhalation R8 - Contact with combustible material may cause fire R43 - May cause sensitization by skin contact R50/53 - Very toxic to aquatic organisms, may cause long-term adverse effects in the aquatic environment. R34 - Causes burns |
| Safety Description | S53 - Avoid exposure - obtain special instructions before use. S17 - Keep away from combustible material. 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. S36/37/39 - Wear suitable protective clothing, gloves and eye/face protection. S26 - In case of contact with eyes, rinse immediately with plenty of water and seek medical advice. |
| UN IDs | UN 1479 5.1/PG 2 |
| WGK Germany | 3 |
| RTECS | GB2880000 |
| TSCA | Yes |
| Hazard Class | 5.1 |
| Packing Group | III |
Chromic acid (H2CrO4), diammonium salt - Upstream Downstream Industry
| Raw Materials | Chromium(VI) oxide Ammonia |
| Downstream Products | Furfuryl alcohol |
Chromic acid (H2CrO4), diammonium salt - Nature
Open Data Verified Data
yellow monoclinic crystals. The relative density was 1. 91. Decomposition was initiated by heating to 180 °c. Soluble in cold water, slightly soluble in ammonia, acetone, insoluble in alcohol. Long-term storage can be decomposed to release ammonia, partial conversion to ammonium dichromate.
Last Update：2024-01-02 23:10:35
Chromic acid (H2CrO4), diammonium salt - Preparation Method
Open Data Verified Data
- neutralization method: Ammonium chromate solution is produced by adding aqueous ammonia into a reactor containing ammonium dichromate to carry out neutralization reaction, followed by evaporation and concentration, cooling crystallization, solid-liquid separation, and drying to obtain a final ammonium chromate product.
- double decomposition method: potassium chromate is added into a reactor containing water, and ammonium sulfate solution is slowly added under stirring for double decomposition reaction to generate ammonium chromate and potassium sulfate solution, which is filtered to remove potassium sulfate and concentrated by evaporation, cooling crystallization, solid-liquid separation, drying, prepared ammonium chromate products.
Last Update：2022-01-01 11:00:40
Chromic acid (H2CrO4), diammonium salt - Use
Open Data Verified Data
mainly used as mordant, photographic coating sensitizer, Catalyst, corrosion inhibitor.
Last Update：2022-01-01 11:00:39
Chromic acid (H2CrO4), diammonium salt - Safety
Open Data Verified Data
see sodium chromate.
Last Update：2022-01-01 11:00:40
Chromic acid (H2CrO4), diammonium salt - Reference Information
| 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 (℃): 25g/0 ℃;29.2g/10 ℃;34g/20 ℃;39.3g/30 ℃;45.3g/40 ℃ 59g/60 ℃;76.1g/80 ℃ |
| toxicity | see sodium chromate. |
| purpose | mainly used as mordant, photographic coating sensitizer, Catalyst, corrosion inhibitor. used as analytical reagent, oxidant and mordant |
| production method | neutralization method the neutralization reaction is carried out in a reactor containing ammonium dichromate and ammonia water to generate ammonium chromate solution, after evaporation and concentration, cooling crystallization, solid-liquid separation, drying, prepared ammonium chromate products. Its (NH4)2Cr2O7 2NH4OH → 2(NH4)2CrO4 H2O double decomposition method to add potassium chromate into the reactor containing water, slowly adding ammonium sulfate solution under stirring for double decomposition reaction, generate ammonium chromate and potassium sulfate solution, filter to remove potassium sulfate, by evaporation and concentration, cooling crystallization, solid-liquid separation, drying, prepared ammonium chromate product. K2CrO (NH4)2SO4 →(NH4)2CrO4 K2SO4 |
| category | oxidant |
| toxicity grade | high toxicity |
| Acute toxicity | Reference range: Peritoneal-rat LD50: 57 mg/kg; Peritoneal-mouse LD50: 32 mg/kg |
| explosive hazard characteristics | initiation by heat or vibration |
| flammability hazard characteristics | toxic chromium oxide, nitrogen oxide and ammonia smoke generated at high temperature |
| storage and transportation characteristics | The warehouse is ventilated and dried at low temperature; It is stored separately from the reducing agent |
| fire extinguishing agent | dry powder, foam, sand, carbon dioxide, water mist |
| Occupational Standard | TWA 0.05 mg (chromium)/m3 |
| toxic substance data | information provided by: pubchem.ncbi.nlm.nih.gov (external link) |
Last Update：2024-04-10 22:29:15
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