Arsenic
Elemental
Arsenic
As
Atomic Number - 33
During the Bronze Age, arsenic was often included in the bronze,
mostly as an impurity, to make the alloy harder.
The History Says
Arsenic has been known and used in Persia and elsewhere since ancient
times. The symptoms of arsenic poisoning were not defined, hence it
was frequently used for murder until the advent of the Marsh test, a
sensitive chemical test for its presence.
The Present Scenario
Recent years have seen fatal animal poisonings, and serious human
poisonings resulting from the ingestion of wood ash either directly or
indirectly from copper arsenate (CCA) timber (the lethal human dose is
approximately 20 grams of ash - roughly a tablespoon). Scrap CCA
construction timber continues to be widely burnt through ignorance, in
both commercial, and domestic fires.
ARSENIC
IS a chemical element in the peridic table with an atomic number 33.
It is notoriously poisonous metalloid having three allotropic forms
i.e. yellow, black and grey, and is similar to phosphorus. It oxidizes
to arsenic trioxide when heated rapidly and have a garlic odor.
Arsenic and some of its compounds also sublimes upon heating. It gets
converted to a gaseous form. Elemental arsenic occurs in two solid
forms, yellow and gray/metallic, but it do not always form in its
elemental state. It is more common in sulfides and sulfosalts, like
arsenopyrite, realgar, orpiment, lollingiten and tennantite.
Since the arsenic bearing ores are abundant and native arsenic is
rare, it makes one of the important ore of itself. Native arsenic is
found in silver ore veins and is processed along with the silver ore.
It forms a minor source of arsenic.
Physical Properties of Arsenic
| Color |
Tin-white that quickly
tarnishes to dark gray or black. |
| Luster |
Metallic but the tarnish will
often dull the luster dramatically. |
| Transparency |
Crystals are opaque. |
| Cleavage |
It is perfect in one direction
(basal), but is rarely visible. |
| Fracture |
Uneven |
| Hardness |
3 - 4 |
| Specific gravity |
5.4 - 5.9+ (It is somewhat
heavy for a metallic mineral). |
| Streak |
Black |
Associated
Minerals of Arsenic
- Silver
- Dyscrasite
- Barite
- Cinnabar
- Nickeline
Occurrences of Arsenic
- Vosges, France
- Kongsberg, Norway
- Saxony and Harz Mountains, Germany
- Honshu, Japan
- England
- Italy
- Arizona and New Jersey, USA
Precautions
with Arsenic
Arsenic and many compounds of arsenic are especially potent poisons.
It disrupts the digestive system which can lead to death from shock.
Both, arsenic and its compound inhibit the enzyme lipothiamide
pyrophosphate, an important enzyme of metabolism.
The toxicity is manifested a severe gastro enteritis and diarrhoea in
animals. This is also described as rice gruel type. Post mortems
reveal brick red colored mucosa because of the sever haemorrhage.
The symptoms of arsenic poisoning are as follows:
- Violent
stomach pains, vomiting and delirium.
- Mild
headaches progressing towards usual light headedness if it goes
untreated.
At the time of ingestion of arsenic, it is suggested to immediately
ingest 5 charcoal tablets, so that it helps soak up the arsenic and
then pass it through the system naturally. Eating food with sulphur
like eggs and onions neutralizes arsenic in a natural, nonchemical
way. Presently, there are many chemical and synthetic methods being
used to treat its poisoning.
Note:- Seek medical advice immediately if arsenic
poisoning is suspected. Never treat presumed arsenic poisoning by
yourself.
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