Generality
Cyanide is the chemical term that identifies any chemical compound containing the cyan (CN) group.
The cyan group is a molecule formed by the union of a carbon atom and a nitrogen atom.
Examples of inorganic cyanide are hydrogen cyanide, sodium cyanide, potassium cyanide and cyanogen chloride.
Examples of organic cyanide, on the other hand, are nitriles, contained in the cores of different fruits (apricots, peaches, cherries, etc.).
Cyanides are chemical substances that are widely used in manufacturing, from the paper industry to the metallurgical, plastic, etc.
What is cyanide?
A cyanide is any chemical compound containing the cyano (CN ) group.
The cyan group is the fruit of the union of a carbon atom (the C of CN) to a nitrogen atom (the N of CN). The link between carbon and nitrogen is a triple covalent bond. The total charge present on the CN group is negative, therefore, the cyan group is an anion .
THE CIANURO AS POISON: THE INORGANIC CYANURS
In the common imagination, the term cyanide refers to a powerful poison, with lethal effects.
From the chemical point of view, cyanides that act as powerful poisons are inorganic cyanides, such as sodium cyanide (NaCN), potassium cyanide (KCN) and cyanogen chloride (ClCN).
WHERE IS THE INORGANIC TYPE OF CHIANUR?
Any type of inorganic cyanide derives from the dissociation of hydrocyanic acid ( HCN or hydrogen cyanide ) or one of its salt (which in turn can be a cyanide).
Hydrocyanic acid is an inorganic molecule, the result of the union of a cyan group (CN) with a hydrogen atom (H). It is a highly toxic weak acid and can be considered a particular example of inorganic cyanide.
Please note : sodium cyanide and potassium cyanide are two salts of hydrocyanic acid.
Cyanogen chloride, on the other hand, is a derivative of a salt of hydrocyanic acid; to be precise, it is a derivative of sodium cyanide. The oxidation of sodium cyanide with chlorine forms cyanogen chloride.
ORGANIC CYANUR
In nature, the cyano anion CN forms chemical compounds also with organic molecules (eg methyl groups, etc.), giving rise to types of organic cyanide .
Also known as nitriles, organic cyanides are mildly toxic or only become so on certain occasions; in any case, they are less and less poisonous than inorganic cyanides.
Property
The properties of a cyanide depend on which atoms are linked to the cyano CN group.
Hydrocyanic acid is a pale or colorless blue liquid, at room temperature, while it is a colorless gas at high temperatures. Both in liquid and in gaseous form, it has an odor that resembles that of bitter almonds.
Sodium cyanide and potassium cyanide appear as white powders and emanate - like hydrocyanic acid - an odor comparable to that of bitter almonds.
Cyanogen chloride is a colorless liquefied gas, heavier than air and with a particular pungent odor.
Where is it?
In nature, as well as in the pits of some fruits, cyanide is also present in different species of plants; the plants keep it in the leaves and / or in the bark and use them to defend themselves from herbivores.
In addition to plants, other living things that produce cyanide (or substances containing the cyano CN group) are some bacteria and some fungi.
CIANURO AS A COMBUSTION PRODUCT
Hydrogen cyanide is a possible product of combustion processes.
To be precise, it is present in the exhaust of internal combustion engines, in the cigarette smoke that is produced during the combustion of the latter and in the fumes deriving from the fusion of the acrylonitrile-based plastic materials (an organic compound containing a cyan group CN).
uses
In manufacturing, cyanide is widely used. In fact, it is used by the paper industry (to produce paper), the textile industry (to produce fabrics, etc.), the plastic manufacturing industry, the photographic industry (to produce all those chemical compounds for development of the photos), the metallurgical industry (to produce steel and iron, to wash metals and for galvanizing), the industry that deals with the treatment of waste water and the industry for the production of pesticides (against pests etc.) for various types of environment.
For obvious reasons, traces of cyanide can be found in the waste products of all the aforementioned activities.
PAST USE
In the past, hydrogen cyanide was used for tragic purposes.
For example, during the Second World War, Nazi Germany used it - under the name of Zyklon B - as a toxic agent in the gas chambers of the death camps.
spread
Cyanide has the ability to spread in water, soil and air (NB: it is in the form of gas in the air).
Humans can come into contact with cyanide by breathing in contaminated air, drinking contaminated water, eating contaminated food or touching contaminated soil.
A "daily" source of cyanide - to which many people are exposed - is cigarette smoking.
Effects
After exposure, cyanide takes little time to enter the bloodstream and spread into the body, through the blood.
The human body reacts to the presence of cyanide in different ways, depending on whether the doses are very low or medium-high.
When the doses are very low, the cyanide turns, through a series of cellular reactions, into thiocyanate, a chemical compound harmless to health and which the human being eliminates through the urine. Moreover, always at low doses, cyanide combines with vitamin B12 and the resulting combination seems to have beneficial effects both on nerve cells and on blood cells.
When, on the other hand, the doses are medium-high, the ability of the human body to transform cyanide into thiocyanate is suppressed (due to an excessive workload) and the toxic substance in question prevents the cells from using oxygen. The inability of cells to use oxygen leads to the death of the cells themselves.
The heart, the respiratory system and the central nervous system are most affected by a large exposure to cyanide.
Note : it is advisable to specify, for the avoidance of doubt, that chronic exposure to very small doses of cyanide can have toxic effects similar to those induced by exposure to medium-high doses.
TOXICITY
The toxic effects on human health, on the part of cyanide, depend on three factors: the dose of toxic substance with which it came into contact, the duration of exposure and the type of cyanide.
In general, exposure to intermediate doses of cyanide involves:
- Breath acceleration;
- Sense of restlessness;
- Dizziness;
- Sense of weakness;
- Headache
- Nausea and vomiting;
- Heart rate acceleration.
If the cyanide doses are high, the following events are associated:
- Convulsions;
- Hypotension;
- Slow heart rate;
- Loss of consciousness;
- Shortness of breath and difficulty breathing, due to lung problems;
- Cardiac arrest.
The effects of cyanide exposure begin to show up after just a few seconds / minutes. The dose mainly affects the speed of onset of effects.
Generally death from exposure to cyanide occurs as a result of severe respiratory failure or cardiac arrest.
LONG-TERM EFFECTS
According to various clinical investigations, people who survive massive cyanide exposure would tend to develop permanent neurological problems, some of which mimic symptoms very similar to those of Parkinson's disease .
LETHAL DOSE
When cyanide doses are lethal, experts say " death from cyanide poisoning ".
For sodium cyanide and potassium cyanide, the lethal dose for humans is 200-300 mg; for hydrogen cyanide, on the other hand, the lethal dose for humans is 50 mg.
Therapy
Exposure to toxic doses of cyanide represents a medical emergency to be treated very quickly and in the most appropriate manner.
In general, the very first therapeutic indications are:
- Move as quickly as possible from the place / environment of exposure and move to an uncontaminated place;
- Take off your clothes, in case they are contaminated, and close them in a plastic bag;
- Wash the eyes every 10-15 minutes, if they burn;
- Wash any part of the skin that has come into contact with the cyanide with soap and water;
- Call medical help.
Upon arrival of medical help, they will complete the treatment, supplying oxygen to the person concerned and an antidote.
The antidotes against exposure to conspicuous doses of cyanide are sodium thiosulphate, sodium nitrite and hydroxocobalamin.
