Name | telluric acid |
Synonyms | telluric tellurate TELLURIC ACID telluric acid telluric(vi)acid TELLURATE HYDROGEN telluriumhydroxide orthotelluric acid telluricacid(h6teo6) Hydrogen tellurate(VI) hexahydroxy-lambda~6~-tellane |
CAS | 7803-68-1 |
EINECS | 232-267-6 |
InChI | InChI=1/H6O6Te/c1-7(2,3,4,5)6/h1-6H |
Molecular Formula | H6O6Te |
Molar Mass | 229.64404 |
Density | 3.068; d 3.163 |
Melting Point | 136°C |
Boling Point | 0℃ |
Water Solubility | g H2TeO6/100g H2O: 16.2 (0°C), 41.6 (20°C), 155 (100°C) [LAN05]; tends to polymerize; soluble dilute HNO3 [MER06] |
Solubility | H2O: 0.1g/mL, clear, colorless |
Appearance | white monoclinic crystals |
Color | White to Almost white |
Solubility Product Constant(Ksp) | pKsp: 53.52 |
Maximum wavelength(λmax) | ['275nm(H2O)(lit.)'] |
Merck | 14,9120 |
pKa | 7.7(at 25℃) |
Physical and Chemical Properties | Telluric acid is a colorless crystal, which is prepared by the interaction of sulfuric acid with barium tellurite or the oxidation of elemental tellurium with a strong oxidant. It is stable in air and can be used to prepare other telluric acid and tellurite and as an oxidant. Tellurium is oxidized to telluric acid with a strong oxidant. There are two variants: monoclinic and cubic. Monotrope density of 3.071g/cm3, cubic 3 .17g/cm3 is soluble in water, difficult to dissolve in concentrated nitric acid, heating 100 to 200 deg C dehydration to produce intermediate product (H2TeO4)n, and finally completely converted into acid anhydride teo3. It is a weak acid similar to that of carbonic acid. |
Hazard Symbols | Xn - Harmful |
Risk Codes | 20 - Harmful by inhalation |
Safety Description | S22 - Do not breathe dust. S36/37/39 - Wear suitable protective clothing, gloves and eye/face protection. S38 - In case of insufficient ventilation, wear suitable respiratory equipment. |
UN IDs | UN 3284 6.1/PG 3 |
WGK Germany | 3 |
RTECS | WY2350000 |
FLUKA BRAND F CODES | 8 |
Hazard Class | 6.1(a) |
Packing Group | II |
EPA chemical substance information | information provided by: ofmpeb.epa.gov (external link) |
production method | 1. Theoretical amounts of anhydrous potassium carbonate (pure grade), water and a small amount of 30% hydrogen peroxide (pure grade) were added to the ground reagent tellurium dioxide, which was continuously stirred and heated to 105-110 oC for 30min, when the bubbles no longer overflow, the mixture was cooled, the insolubles were filtered off, the filtrate was diluted with water and then KY-2(H-type) cation exchange resin was added in small portions. The PH of the mixture was controlled to <3, the resin was filtered off and the resin was washed several times with water, the washing liquid was incorporated into the filtrate, and the solution was passed through the column filled with KY-2(H-type) washing exchange column at a certain speed, combine the washing liquid and the solution, heat and evaporate until the crystallization film appears, cool, add 95% ethanol twice the volume of the solution, let stand and filter, wash the crystals with 95% ethanol, then dry under vacuum, it is the finished product. 2.13g of the tellurium powder was charged into a round-bottom flask with a reflux condenser and completely wetted with 5mL 50% nitric acid. The reaction device is placed in a fume hood, and 150mL 10% chloric acid solution is added in portions, which can be heated to make the reaction intense. At this time, the solution should be in a boiling state, and a large amount of chlorine gas is generated, which is heated and refluxed for 30min, the tellurium was completely dissolved. First, the solution is heated and evaporated by direct fire, and then evaporated on a water bath until crystals appear. Under stirring, the crystals are cooled in an ice water bath to precipitate fine white crystals. The crystals were filtered off, dissolved with hot water and recrystallized once. Filter with a glass sand core funnel, wash with a small amount of ice water, then with ethanol and ether, and finally dry in a vacuum dryer with P2O5. 3. A suspension of 10g of TeO2 in 40ml of concentrated nitric acid and 100mL ml of water was heated to boiling and A% solution of potassium permanganate was slowly added in portions with vigorous stirring, 5ml being added every 5min and then stirred and boiled. When all the potassium permanganate solution was added, the solution was maintained at boiling temperature for 50min, which reduced the amount of MnO2 generated. The 3% H2O2 solution was then slowly added until the MnO2 was completely dissolved and became a clear solution. When the solution was evaporated to about 60g, 10ml of concentrated nitric acid was added and allowed to stand for 24h to precipitate the crystallization of the original telluric acid. The mother liquor was decanted and evaporated to about 25g and then subjected to the same treatment with 10ml of concentrated nitric acid to obtain partial crystals. The two crystals obtained were combined and washed three times with concentrated nitric acid, each time with 10ml of nitric acid, and the crystals were dried as much as possible after each washing. The crystals were then recrystallized once with a solution consisting of 25ml of water and 17ml of concentrated nitric acid and once with distilled water. Finally, the crystals were washed with a small amount of ice-water, ethanol and diethyl ether in this order and dried in a vacuum desiccator with P2O5. |