I have compiled a list of sources for the elements that are available to the amateur chemist. Krypton will be discussed here.
Krypton, like all other noble gases, is a colorless, odorless, and tasteless gas. It is quite heavy and quite inert, but does form a few compounds. Krypton is much rarer in the atmosphere, from which it is extracted by distillation. Therefore, it is much more expensive. Krypton produces a gray-green light when introduced into an electric arc.
In element form: Krypton is used in many flashlight bulbs.
In compound form: No sources found.
Here is my sample of krypton. It is a couple of flashlight bulbs.
I have compiled a list of sources for the elements that are available to the amateur chemist. Bromine will be discussed here.
Bromine is a dark red liquid, one of the two elements liquid at STP on the periodic table. Bromine is a highly reactive member of the halogen group. For example, aluminium reacts violently with bromine when placed in it. Bromine has a high vapor pressure and will quickly evaporate. Bromides are similar to chlorides, although more easily oxidized. Bromine dissolves in water to form a red solution. Bromine forms a series of oxyanions which are strong oxidizers and somewhat toxic. Bromates were used to treat flour before they were banned or discouraged in many places. Bromine is easily extracted from bromide by reaction with concentrated sulfuric acid.
In element form: Sodium bromide reacts with sulfuric acid to make bromine vapor and liquid. It needs to be distilled in all-glass apparatus. Bromine water, still corrosive but much safer, can be made in an impure form by reacting a mixture of sodium bromide, sodium hypochlorite, and hydrochloric acid.
In compound form: Sodium bromide is used as a bromide reserve in spas and pools and can be cheaply bought.
Here is my sample of bromine. It is a clear plastic vial of bromine water, which later gets cloudy and corroded.
Have fun with lead chemistry, but be safe with small amounts! All of my lead experiments (I also formed the sulfate, bromide, chloride, dioxide, monoxide, etc.) used about 200 mg of lead, which is quite a small amount of metal.
I have compiled a list of sources for the elements that are available to the amateur chemist. Selenium will be discussed here.
Selenium, like most nonmetals, is quite a unique and interesting element. Selenium is necessary in small quantities in the human body, but toxic in larger amounts. The element itself has three forms: a glassy, black, nonmetallic form; a red, powdery, nonmetallic form; and a gray, malleable, semimetallic form. This gray form is the most useful and the most common form of selenium. Selenium has the interesting property of changing its conductivity upon exposure to light. Therefore, it was used in the first photodetectors (cadmium sulfide is used now). Selenium forms a highly toxic and smelly dioxide which is the primary selenium compound. Selenium forms binary molecular compounds as well as anionic covalent complexes like selenite and selenate. Selenides replace a small amount of sulfide in many ores, making selenium a common byproduct in processes like copper production.
In element form: Selenium rectifiers contain a thin layer of selenium metal, as well as old photocopier machines and light meters.
In compound form: Selenium sulfide is used in Selsun Blue shampoo. Organic selenium complexes, as well as the inorganic selenites and selenates, are both used in selenium vitamin supplements. Selenium toners contain sodium selenite.
I do not have any verifiable elemental selenium. I do have a few specks that precipitated out when some selenium vitamin supplement slurry was electrolyzed, but of course they are not selenium. I plan to purchase pure elemental selenium in the near future, after which this page will be updated.
I have compiled a list of sources for the elements that are available to the amateur chemist. Arsenic will be discussed here.
Arsenic is a highly toxic metalloid that comes in several allotropes. The nonmetallic forms of arsenic are least stable, such as yellow arsenic, while the common metallic gray arsenic predominates. Gray arsenic is a dull solid. When heated in air, it burns to the trioxide. Arsenic dissolves in nitric acid to form the oxide as well. Arsenic is found in a wide range of minerals, and is almost always extracted as a byproduct. For example, arsenopyrite is iron arsenide sulfide. When this is roasted, both arsenic and sulfur oxides are produced. Arsenic was a common poison until an extremely sensitive test called the Marsh test was developed for it. This produces the gas arsine (AsH3) from arsenic-containing materials and later deposits the arsenic on a glass tube. Even a tiny trace of arsenic will produce a notable coloration on the glass surface.
In element form: Lead wheel weights for cars contain about 1/4% arsenic.
In compound form: Old treated wood contains Chromated Copper Arsenate as the treatment chemical. Infrared LEDs contain gallium arsenide as the semiconductor. High frequency microwave circuits may use gallium arsenide components. Chicken meat also can contain arsenic in the form of roxarsone.
Here is my sample of arsenic. It is one of innumerable lead wheel weights that are continually leaching into the environment from road abrasion after being loosened from vehicle tires.
I have compiled a list of sources for the elements that are available to the amateur chemist. Germanium will be discussed here.
Germanium is a hard, inert, and brittle metalloid from Group 14 on the periodic table. Germanium has properties intermediate between tin and silicon. In the early days of electronics, germanium was the primary semiconducting material because purity is not essential for it to work. Silicon, because of its great abundance, has since superseded germanium in almost all electronics applications. Germanium forms quadrivalent covalent compounds with very low boiling points. Germanium can be used as a nutritional supplement but this use is questionable. Germanium dioxide is a white amphoteric solid that can dissolve in both acids and bases.
In element form: Germanium windows were used for motion sensors in the past. Germanium diodes are still found in old electronics equipment.
In compound form: Germanium compounds are used in the phosphors for mercury vapor lamps. Germanium dioxide is used in fiber optic cables.
Here is my sample of germanium, small germanium crystals from old diodes.