7782-49-2
CHEMICAL AND PHYSICAL PROPERTIES
| Physical Description | Selenium is a reddish colored powder that may become black upon exposure to air. It is toxic by ingestion. It is used to manufacture electronic components and rubber. |
|---|---|
| Color/Form | Selenium exists in several allotropic forms. 3 are generally recognized ... Selenium can be prepd with either amorphous or crystalline structure. ... Amorphous is either red, in powder form or black, in vitreous form. Crystalline monoclinic selenium is deep red; crystalline hexagonal form, the most stable variety, is a metallic gray. |
| Boiling Point | 1265 °F at 760 mmHg (NIOSH, 2023) |
| Melting Point | 392 °F (NIOSH, 2023) |
| Solubility | Insoluble (NIOSH, 2023) |
| Density | 4.28 (NIOSH, 2023) - Denser than water; will sink |
| Vapor Pressure | 0 mmHg (approx) (NIOSH, 2023) |
| LogP | 5 |
| Decomposition | When heated to decomp ... emits toxic fumes of /selenium/. |
| Viscosity | 221 mPa-S (= cP) at 220 °C; 70 cP at 360 °C |
| Corrosivity | Strongly corrosive, especially at high temperature. |
| Heat of Combustion | -225.1 kJ/mol at 298 K |
| Heat of Vaporization | 59.7 kJ/mol |
| Surface Tension | 105.5 dyn/cm at 220 °C; 95.2 dyn/cm at 310 °C (liquid) |
| Other Experimental Properties | Combines directly with hydrogen, with the halogens (excluding iodine); oxidized to selenious acid by nitric acid, to selenic acid by sulfuric acid; reduces hot aqueous soln of silver and gold salts with formation of silver selenide and metallic gold, respectively |
| Chemical Classes | Other Classes -> Other Inorganic Compounds |
SAFETY INFORMATION
| Signal word | Danger |
|---|---|
| Pictogram(s) |
 Skull and Crossbones Acute Toxicity GHS06  Health Hazard GHS08 |
| GHS Hazard Statements |
H373:Specific target organ toxicity, repeated exposure H413:Hazardous to the aquatic environment, long-term hazard |
| Precautionary Statement Codes |
P260:Do not breathe dust/fume/gas/mist/vapours/spray. P264:Wash hands thoroughly after handling. P264:Wash skin thouroughly after handling. P273:Avoid release to the environment. P314:Get medical advice/attention if you feel unwell. P301+P310:IF SWALLOWED: Immediately call a POISON CENTER or doctor/physician. |
COMPUTED DESCRIPTORS
| Molecular Weight | 78.97 g/mol |
|---|---|
| Hydrogen Bond Donor Count | 0 |
| Hydrogen Bond Acceptor Count | 0 |
| Rotatable Bond Count | 0 |
| Exact Mass | 79.91652 g/mol |
| Monoisotopic Mass | 79.91652 g/mol |
| Topological Polar Surface Area | 0 Ų |
| Heavy Atom Count | 1 |
| Formal Charge | 0 |
| Complexity | 0 |
| Isotope Atom Count | 0 |
| Defined Atom Stereocenter Count | 0 |
| Undefined Atom Stereocenter Count | 0 |
| Defined Bond Stereocenter Count | 0 |
| Undefined Bond Stereocenter Count | 0 |
| Covalently-Bonded Unit Count | 1 |
| Compound Is Canonicalized | Yes |
PRODUCT INTRODUCTION
description
Selenium is a naturally occurring mineral element that is distributed widely in nature in most rocks and soils. In its pure form, it exists as metallic gray to black hexagonal crystals, but in nature it is usually combined with sulfide or with silver, copper, lead, and nickel minerals. Most processed selenium is used in the electronics industry, but it is also used: as a nutritional supplement; in the glass industry; as a component of pigments in plastics, paints, enamels, inks, and rubber; in the preparation of pharmaceuticals; as a nutritional feed additive for poultry and livestock; in pesticide formulations; in rubber production; as an ingredient in antidandruff shampoos; and as a constituent of fungicides. Radioactive selenium is used in diagnostic medicine.