|Name, Symbol, Number||arsenic, As, 33|
|Group, Period, Block||15 (VA), 4 , p|
|Density, Hardness||5727 kg/m3, 3.5|
|Atomic weight||74.92160 amu|
|Atomic radius (calc.)||115 (114) pm|
|Covalent radius||119 pm|
|van der Waals radius||185 pm|
|Electron configuration||[Ar]33d10 4s2 4p3|
|e- 's per energy level||2, 8, 18, 5|
|Oxidation states (Oxide)||+-3,5 (mildly acidic)|
|State of matter||solid|
|Melting point||1090 K (1503 ðF)|
|Boiling point||887 K (1137 ðF)|
|Molar volume||12.95 ×1010-6 m3/mol|
|Heat of vaporization||34.76 kJ/mol|
|Heat of fusion||369.9 kJ/mol|
|Vapor pressure||__ Pa at __ K|
|Speed of sound||__ m/s at __ K|
|Electronegativity||2.18 (Pauling scale)|
|Specific heat capacity||330 J/(kg*K)|
|Electrical conductivity||3.45 106/m ohm|
|Thermal conductivity||50 W/(m*K)|
|1st ionization potential||947.0 kJ/mol|
|2nd ionization potential||1798 kJ/mol|
|3rd ionization potential||2735 kJ/mol|
|4th ionization potential||4837 kJ/mol|
|5th ionization potential||6043 kJ/mol|
|6th ionization potential||12310 kJ/mol|
|Most stable isotopes|
|SI units & STP are used except where noted.|
Arsenic is a chemical element in the periodic table that has the symbol As and atomic number 33. This is a notorious poisonous metalloid that has three allotropic forms; yellow, black and grey. Arsenic and its compounds are used as pesticides, herbicides and insecticides and various alloys.
|Table of contents|
6 Related topics
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Arsenic is chemically very similar to its predecessor phosphorus, so much so that it will partly substitute for it in biochemical reactions and is thus poisonous. When heated it rapidly oxidizes to arsenous oxide, which has a garlic odor. Arsenic and some arsenic compounds can also sublime upon heating, converting to gaseous form directly. Elemental arsenic is found in two solid forms: yellow and gray/metallic, with specific gravities of 1.97 and 5.73, respectively.
Lead arsenate has been used, well into the 20th century, as a pesticide on fruit trees (resulting in neurological damage to those working the sprayers), and copper arsenate has even been recorded in the 19th century as a coloring agent in sweets. Other uses;
- Various agricultural insecticides and poisons.
- Gallium arsenide is an important semiconductor material, used in integrated circuits. Circuits made using the compound are much faster (but also much more expensive) than those made in silicon. Unlike silicon it is direct bandgap, and so can be used in is used in laser diodes and LEDs to directly convert electricity into light.
- Arsenic trioxide has been used in hematology to treat patients with acute promyelocytic leukemia that are resistant to ATRA treatment
- Arsenic trioxide is used in Australia for treating termite infestations in houses.
- Also used in; bronzing, pyrotechny
HistoryArsenic (Greek arsenikon, meaning "yellow orpiment") has been known and used since ancient times. It has been frequently used for murder, the symptoms of arsenic poisoning being somewhat ill-defined, until the advent of the Marsh test, a sensitive chemical test for its presence.
There is a massive epidemic of arsenic poisoning in Bangladesh. This is due to the massive tube well drinking-water program instigated by western NGOss in the late twentieth century, who failed to test for arsenic in the groundwater. Hundreds of thousands of people are affected. It is thought to be the worst mass-poisoning in history, and possibly the worst environmental disaster in history.
The most important compounds of arsenic are white arsenic, its sulfide, Paris green, calcium arsenate, and lead arsenate. Paris green, calcium arsenate, and lead arsenate have been used as agricultural insecticides and poisons. It is sometimes found native, but usually combined with silver, cobalt, nickel, iron, antimony, or sulfur.