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.