Holmium atomic absorption standard solution
Holmium atomic absorption standard solution
CAS: 7440-60-0;22541-22-6
Molecular Formula: Ho
Holmium atomic absorption standard solution - Names and Identifiers
Holmium atomic absorption standard solution - Physico-chemical Properties
| Molecular Formula | Ho |
| Molar Mass | 164.93 |
| Density | 8.8 g/mL at 25 °C (lit.) |
| Melting Point | 1474 °C |
| Boling Point | 2695 °C |
| Water Solubility | reacts slowly with H2O, soluble dilute acids [HAW93] |
| Appearance | ingot |
| Specific Gravity | 8.795 |
| Color | Silver-gray |
| Exposure Limit | ACGIH: TWA 2 ppm; STEL 4 ppmOSHA: TWA 2 ppm(5 mg/m3)NIOSH: IDLH 25 ppm; TWA 2 ppm(5 mg/m3); STEL 4 ppm(10 mg/m3) |
| Merck | 13,4747 |
| Sensitive | Air & Moisture Sensitive |
Holmium atomic absorption standard solution - Risk and Safety
| Risk Codes | R34 - Causes burns R11 - Highly Flammable R8 - Contact with combustible material may cause fire |
| Safety Description | S22 - Do not breathe dust. S24/25 - Avoid contact with skin and eyes. S36 - Wear suitable protective clothing. S26 - In case of contact with eyes, rinse immediately with plenty of water and seek medical advice. S23 - Do not breathe vapour. S45 - In case of accident or if you feel unwell, seek medical advice immediately (show the label whenever possible.) S36/37/39 - Wear suitable protective clothing, gloves and eye/face protection. S27 - Take off immediately all contaminated clothing. |
| UN IDs | UN 3089 4.1/PG 2 |
| WGK Germany | 3 |
| FLUKA BRAND F CODES | 1-10 |
| TSCA | Yes |
| HS Code | 28053090 |
| Hazard Class | 4.1 |
| Packing Group | II |
Holmium atomic absorption standard solution - Reference Information
| EPA chemical information | Information provided by: ofmpub.epa.gov (external link) |
| Introduction | Holmium is a chemical element, its chemical symbol is Ho, and its atomic number is 67. It belongs to the lanthanide series and is also one of the rare earth elements. Holmium is solid at room temperature and pressure. The soft, malleable silver element of the lanthanide metal. It appears in combination with other lanthanides. It was discovered by J.L.Soret in 1878; it was discovered by P.T.Cleve in 1879. The first ionization energy 6.02 electron volts. It has a metallic luster. It works slowly with water and dissolves in dilute acid. The salts are yellow. The oxide Ho2O2 is pale green. Soluble in mineral acid to produce trivalent ionic yellow salt. Made by reducing holmium fluoride HoF3 · 2H2O with calcium. Like dysprosium, it is a metal that can absorb neutrons produced by nuclear fission. In the nuclear reactor, on the one hand, continuous combustion, on the other hand, control the speed of the chain reaction. There are 35 isotopes of holmium, of which 165Ho is the most stable. The rest are synthetic radioisotopes. |
| Discovery history | In the second half of the 19th century, due to the discovery of spectral analysis and the publication of the periodic table of elements, coupled with the progress of the electrochemical separation process of rare earth elements, More promoted the discovery of new rare earth elements. The spectral absorption band of holmium was noticed by Swiss chemists Delafontaine and Soret in 1878, who announced the existence of "element X". In 1879, Cleve, a Swede, later discovered this element independently while working on the earth in Serbia. The holmium element is named after Stockholm, the Swedish capital of Cleve's hometown. |
| Source | Holmium is the 12 highest content of rare earths found in the earth's crust. Although it ranks 50th among the most abundant elements on Earth, it is also one of the least abundant lanthanide metals, found in the gabbro and monazite sands of South Africa and Australia and in the beach sands of Florida and Carolina in the United States. Monazite sand contains about 50% of rare earth mixtures, but holmium only accounts for 0.05% (weight). Now, a small amount of holmium can be prepared through an ion exchange process. |
| application | (1) used as an additive for metal halogen lamps. metal halogen lamps are gas discharge lamps, which are developed on the basis of high-pressure mercury lamps. Its characteristic is that the bulbs are filled with various rare earth halides. At present, rare earth iodide is mainly used, which emits different spectral light colors during gas discharge. The working substance used in the holmium lamp is holmium iodide, which can obtain a higher concentration of metal atoms in the arc area, thereby greatly improving the radiation efficiency. (2) Holmium can be used as an additive for yttrium iron or yttrium aluminum garnet;(3) Holmium-doped yttrium aluminum garnet (Ho:YAG) can emit 2μm laser, and human tissues have a high absorption rate of 2μm laser, which is almost 3 orders of magnitude higher than Hd:YAG. Therefore, when using Ho:YAG laser for medical surgery, not only can improve the efficiency and accuracy of the operation, but also can reduce the thermal damage area to a smaller size. The free beam produced by holmium crystals can eliminate fat without generating excessive heat, thereby reducing thermal damage to healthy tissues. It is reported that the treatment of glaucoma with holmium laser in the United States can reduce the pain of patients undergoing surgery. The level of 2μm laser crystals in China has reached the international level, and we should vigorously develop and produce such laser crystals. (4) In the Terfenol-D of magnetostrictive alloy, a small amount of holmium can also be added to reduce the external field required for saturation magnetization of the alloy. (5) In addition, holmium-doped optical fibers can be used to make optical communication devices such as fiber lasers, fiber amplifiers, fiber sensors, etc., which will play a more important role in today's rapid optical fiber communication. |
| Preparation | Holmium is obtained from monazite, slag and other rare earth minerals as a by-product in the recovery process of dysprosium, thulium and other rare earth metals. The production recovery steps for all lanthanides are very similar. These include crushing ore by treatment with hot concentrated sulfuric acid or by caustic melting. The rare earths are separated by an ion exchange process; converted to halide salts; and reduced to metals. Bulk holmium metal is produced by chlorination or fluorination reduction of sodium, calcium or magnesium in a tantalum crucible under argon atmosphere: 2HoF3 3Ca→ 3CaF2 2Ho pure holmium metal is obtained by distilling crude metal at 1,500°C. |
| Properties | Holmberg (Homberg) prepared pure holmium oxide, a yellow oxide in 1911. Holmium exists in pyroxene, monazite and other rare earth mines. It is commercially obtained from monazite and exists in this mineral to a degree of about 0.05%. Holmium has a metallic to bright silver luster. It is relatively soft and malleable, and is stable in dry air at room temperature, but will oxidize rapidly in humid air and at high temperatures. Holmium has abnormal magnetism. |
Last Update：2024-04-09 02:00:04
