The word "Cyanide" is derived from the Greek "kyanos", meaning dark blue. It was first obtained by the heating of the pigment known as Prussian blue (Fe[Fe(CN)])

Any molecule with the Carbon and Nitrogen atoms bonded together is considered a "cyanide". Cyanide is shown here, with a black Carbon bond to the blue Nitrogen. In this "space-filling" model certain elements are color coded. Nitrogen is often colored blue in molecular models.

Dealing with Cyanide can be a negative experience.

When Carbon makes a triple bond with Nitrogen, they share negatively charged electrons. If the number of negative electrons is not equal to the total number of positive protons in a molecule, the molecule has a net charge and is known as an ion. A negatively charged ion, like cyanide, is known as an anion. The figure below shows some common polyatomic ions.

Cyanide can be deadly.

While not every Cyanide compound is dangerous, Sodium cyanide (NaCN), potassium cyanide (KCN), hydrogen cyanide (HCN), and cyanogen chloride (CNCl) are lethal in small doses.

Cyanide is described as bitter, but not many studies have been performed to test this claim. In a suicide letter left by a man from India after ingesting Cyanide, this morbid property was confirmed: "Doctors, potassium cyanide. I have tasted it. It burns the tongue and tastes acrid."

The NFPA 704 safety diamond shows the hazard of each chemical used in a lab. The 3-0-0-SA rating for Cyanide indicates it is an extreme health hazard.

The National Fire Protection Agency developed the scale to warn of dangers from specific chemicals or areas. Every material used in a chemical lab must have a Material Safety Data Sheet (MSDS) on file that includes the NFPA ratings.

How deadly can a "3-0-0" be?

It doesn't take much Cyanide to kill a human. The lethality of a substance is often measured in the LD50 scale. This is the amount of substance needed to kill 50% of a population (Lethal Dose 50). This is often used in combination with body mass to determine relative concentrations (a small person will need less poison to die than a large person).

The LD50 of water, as an example, is 90g/kg. This means a 75kg person (~165lbs) would need to consume 6750g of water to hit this concentration. While our kidney can process about 1000g of water an hour, a woman died drinking 6 liters of water and holding her pee for a contest.

The LD50 for Sodium Cyanide in rats is about 4.3mg/kg, while the LDLo (Lowest Lethal Dose) recorded in humans was 1.3 mg/kg. That means a 98mg dose (less than 1/10 of a gram) would be enough to kill.

Even water and caffeine can be deadly in high volumes, but Cyanide packs a more potent punch

The Mechanism of Action of CN-; irreversible binding of the heme ring in Cytochrome C

Mechanism of Action

Doctors need to understand how a chemical interrupts the normal function of our physiology to begin to fix it. In the case of CN-, the ion binds to an important protein found in Cytochrome. The heme ring (seen in the figure) usually binds to O2, which is an important step of ATP transport within the mitochondria of our our cells. Without this normal function, our cells can not produce ATP and will die rapidly.

Cyanide murders are rare because of restrictions, but it has a long and famous history of death

In 1978, the Jim Jones religious cult from San Francisco traveled to South America and were forced to drink cyanide laced Kool-Aid at the command of their leader. 912 people died.

8 people died in Chicago in 1983 from random containers of Tylenol spiked with Potassium Cyanide. The murderer was never found, but the event led to tamper-proof packaging.

Hydrogen Cyanide was used in Nazi concentration camps. Vials of KCN were consumed by top Nazi officials, including Hitler's wife, to commit suicide instead of facing justice.

According to FBI documentation on homicide in the US from 1999-2012, while women are far less likely to commit murder at all, they are 7 times more likely to use poison as their method of choice. One of most successful serial killers of all time was an Italian women with a penchant for poisons.

Cyanide has strict access restrictions and is typically only available to those with government authorized research credentials. If you know a smart woman with academic access to Cyanide, don't make her angry!

Cyanide is found naturally in some things that you should refrain from eating.

Apple Seeds

0.6 mg of hydrogen cyanide per gram: 83–500 apple seeds to develop acute cyanide poisoning

Cherry Pits

0.01–1.1 mg of amygdalin (breaks down to HCN in the body): 60 pits of red or black cherries may lead to cyanide toxicity

Peach and Apricot Pits

According to scientific analyses, 4-5 raw apricot seeds contains about 45mg of hydrogen cyanide

Bitter Almonds

Bitter almonds have 40x the cyanide concentration of sweet almonds. 10oz of bitter almonds can provoke cyanide toxicity.

LDLo for Hydrogen Cyanide (Lowest Lethal Dose) recorded in humans was 0.54 mg/kg. It could take as little as 40mg of Cyanide to kill a 150 lb person. While some articles will suggest that amygdalin isn't that dangerous, and advocate for its use in some Chinese medicine, are you willing to take the chance?

Cyanide OC (10 pts)

Cyanide can be deadly. The following activities will help you prevent the death of you and your grade at SCHS.

(6 points): Link to your 6 teachers this semester. Include their emails. 1 pt for each complete entry.






(4 points): Identify a chemical at home. Find the MSDS for that chemical, and post the safety diamond for that chemical.

The chemical doesn't have to be dangerous. Look up an ingredient, possibly an ingredient on a product you use.