Arsenic And Old Lies

Alchemist's symbol for Arsenic

Some credit Arsenic with being present at the miraculous birth of organometallic chemistry. He was not.* Let me explain.

Organometallic chemistry is the mystical, covalent union of metallic elements with non-metallic elements--mainly carbon with metals. Saying that Arsenic is a metal is a bit like saying that Barack Obama is black. Arsenic, like phosphorus and sulfur, has different allotropes which is more a mark of non-metallic character.

The element has been known since at least 1250 A.D, but it was known much earlier as its sulfide and its affinity for sulfur is the chief cause for its toxicity. It binds to vital sulfur-containing proteins in cells and shuts them down.

Only about a dozen or so elements are poisonous (not including radioactive ones); the dirty dozen are (in alphabetical order): Aluminum, Antimony, Arsenic, Barium, Beryllium, Cadmium, Chromium (hexavalent), Lead, Mercury, Osmium, Thallium, and Vanadium.

Each name has its own story and its own LD₅₀--some are much worse than others.
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*He because the word Arsenic derives from a Greek word corresponding to male potency. Link

Word Verifications: Isotope and Allotrope

wv = "isotope": noun. The prefix iso is obvious and means the same in Greek.  Topos as in topography has the meaning of place. The word isotope was coined by a Greek-schooled physician named Margaret Todd to convey the notion of at the same place in the Periodic Table. Thus only chemical species with different numbers of protons get separate seats at the Table. Elements having different numbers of neutrons must share the same seat. This is also true for radioisotopes.

wv =  "allotrope": noun:  The prefix allo is related to the Greek allos meaning other. Trope is a confusing root and in my opinion is a vague word having several different meanings. The combination allotrope means a structurally different form of the same element ("Graphite and diamond are allotropes of carbon"). 

Phosphorus and especially sulfur are allotrope-rich. The concept of allotrope is akin to an elemental alias. Sulfur has several different aliases or allotropes. Yes, I like that.

Diamond Soufflé

Graphite (as graphene)

Isn't it obvious looking at their structures why so many attempts to make synthetic diamonds fall flat and make graphite instead?

This is backed by thermodynamic data so argue only if you dare.