16 June 2006

Common Sources for Various Chemicals: Update 1

Aaron Muderick

The Citizen Scientist has reported on the increasing difficulty of finding and purchasing chemicals, many of which were readily available only a few years ago. Aaron Muderick has provided a valuable service to amateur scientists with his exhaustive list of common sources for various chemicals. Aaron's original list was published in The Citizen Scientist on 05 May 2006. Aaron has since expanded his list and made a number of corrections, and the result is presented here. Editor.


As noted in my original article, it has become more difficult to purchase many common chemicals. Paperwork, restrictions, and exorbitant hazmat shipping fees are often required when ordering from traditional chemical supply houses. Therefore, for some time I have been assembling a list of more accessible sources for various chemicals: hardware store, corner grocery, pool supply, fine art store, photography shop, etc. I have not listed chemicals which are only available via mail order.

I hope that this updated version of my original list might be of help to the amateur scientist community. I would expect the list to be very useful when trying to replicate older experiments where the required chemicals were available at the local hardware store of a prior era. The list might also be very helpful to students working on science fair projects and looking to source common chemicals without credit cards, shipping delays, and mail order hassles.

If the chemical you require is not on this list, it can often be manufactured in a home lab, in small quantities, using chemicals which are easier to find or which are less expensive than purchasing a commercial finished product.  For example, the reaction of metallic zinc and acetic acid produces zinc acetate.  The reaction of metallic zinc with hydrochloric acid produces a solution of zinc chloride.

Safety Precautions

It is essential that you abide by any safety warnings and procedures that apply to all chemicals, whether commercial or otherwise. If you are uncertain about proper safety warnings and procedures for a particular chemical, do not make any use of the chemical until you become fully aware of any such warnings and procedures. You can do this by contacting the manufacturer and/or by doing a web search on the name of the chemical and the word "MSDS" (Material Safety Data Sheet). Also, manufacturers should provide an MSDS on request. Neither I nor the Society for Amateur Scientists may be held liable for any consequences of using this information.

Updating the List

I'm sure there are useful chemicals I've missed.  I welcome the input of members of the Society for Amateur Scientists, and the internet community in general, to help improve and expand this list and keep it current.

Acknowledgments

I have received excellent additions, corrections, and feedback from readers Duke McMullan and David Glass.  Thank you for your support.

Editor's Note: Aaron Muderick's list of common sources for chemicals is an invaluable resource for amateur scientists. Please send your comments about the list and suggested additions to Aaron here.

 

Chemical Name Chemical Formula Common or Alternate Name Source and Description
acetic acid CH3COOH Vinegar Grocery stores carry white vinegar which varies between 4-5.5% acetic acid; more concentrated acetic acid (28%) may be purchased at photography supply stores.  Photography stores also carry "Indicator Stop Bath" which is 89% acetic acid and a trace amount of Bromocresol Purple dye.
acetone CH3COCH3 Acetone Nail polish remover is often acetone and fragrance. Fiberglass cleaner is also generally made of acetone and is available at boating supply stores.  Acetone is also available by name at most hardware stores
acetylene gas C2H2 ----- Can be obtained in cylinders from welding supply houses or by the reaction of calcium carbide and water.
acetylsalicylic acid C9H8O4 Aspirin Grocery or drug store,  May contain binders and fillers which dilute purity.
aluminum Al Aluminum Aluminum foil from the grocery store.  Aluminum turnings are available as scrap from machine shops.  Powdered aluminum may be available as a metallic pigment from fine art supply houses.  Fiberglass supply shops offer a similar powdered aluminum as a filler material. Note that this form is often coated with a wax to reduce flammability.
aluminum hydroxide Al(OH)3 alumina hydrate Often blended with magnesium hydroxide in antacid tablets. Also available in pure form as the antacids Alu-cap, Amphojel, and Dialume. Available from some fine art stores as a thickening agent.
aluminum oxide Al2O3 alumina 3/td> Often found sold in nicely graded sizes for use in sandblasting. Welding shops and industrial supply houses will stock them. Also available from certain telescope suppliers where it is used as a grinding agent for optical components.  
aluminum ammonium sulfate AlNH4(SO4)2 Ammonium Alum Available from drug and grocery stores as some styptic pencils for shaving needs.  Also available from fine art supply stores as a mordant for dying and painting.  Found in some organic, health, or bulk foods markets. Sometimes available as a darkroom chemical from photography supply stores.
aluminum potassium sulfate KAl(SO4 )2 12H2O Alum, potassium aluminum sulfate It is used as an astringent to shrink mucus membranes.  Some styptic pencils use it in their formulation. Often sold as a deodorant stone at natural health stores.  Also available as a mordant for clothing dyes (RIT brand and others).
aluminum sulfate Al2(SO4)2 Flocculating Powder Found in Pool supply stores. It is the active ingredient in some antiperspirants (not deodorants). Look for the brand name "Sparkling Clear."
ammonia NH3(aq); NH4OH Ammonia, Ammonium Hydroxide Household ammonia (ammonium hydroxide) is an aqueous solution of ammonia and is available in grocery stores. Anhydrous ammonia is available in cylinders from welding supply houses.
ammonium bicarbonate (NH4)HCO3 Salt of Hartshorn, Baker's Ammonia Also used in Scandinavian baking as a leavening agent. Must be kept sealed from air or it will slowly transform to gaseous ammonia and carbon dioxide. Note that Salt of Hartshorn and Baker's Ammonia can refer to Ammonium Carbonate as well.
ammonium bi fluoride NH4 HF2 ----- Available from hardware stores as a toilet bowl cleaner and rust stain remover.  Also from some automotive supply stores as a car body cleaner. Also used in some glass etching materials including Armour Etch brand.
ammonium bromide NH4 Br ----- Available from some photography stores that cater to the at-home darkroom crowd. Used as a bleach bath in photograph development.
ammonium carbonate (NH4)2CO3 Smelling Salts, Salt of Hartshorn, Baker's Ammonia Grocery or drug store in the first aid section as smelling salts. Also used in Scandinavian baking as a leavening agent. Must be kept sealed from air or it will slowly transform to gaseous ammonia and carbon dioxide. Note that Salt of Hartshorn and Baker's Ammonia can refer to Ammonium Bicarbonate as well.
ammonium chloride (NH4)Cl Soldering Flux Salt of Ammon in plumbing section or Sal Ammoniac in a general hardware store.   It is used to clean the tips of soldering irons and as a solder flux. Note that a lot of soldering flux solutions are zinc chloride, usually acidified with a bit of HCl. Look for labeling that confirms the Ammonium Chloride content. Also available from some photography stores that cater to the at-home darkroom crowd.
ammonium nitrate NH4NO3 Ammonium Nitrate Also called "Nitrate of Ammonia," this fertilizer is available at most garden supply and agricultural supply stores. Small quantities of prilled material are contained inside single-use cold packs that are sold at most grocery stores and pharmacies.
ammonium persulfate (NH4)S2O8 Etching Solution, Ammonium Peroxodisulphate Used as an alternative to ferric chloride for etching circuit boards.  Available at Radio Shack and other electronics supply stores.
ammonium phosphate (NH4)3PO4 Fertilizer Available from garden supply and agricultural supply stores.
ammonium sulfate (NH4)2SO4 ----- Available from garden supply and agricultural supply stores as a fertilizer and also as a pH adjuster for soil.
amylose (C6H9O5)n Corn Starch Corn starch is available at most markets and is used extensively in cooking.
anthocyanin ----- ----- Anthocyanin solution can be prepared by cutting, boiling and then filtering red cabbage.
argon gas Ar ----- Available in cylinders from welding supply houses. Available in small quantities as the inert filler gas inside incandescent light bulbs.
ascorbic acid C6H8O6 Vitamin C Vitamin C tablets sold at the market are primarily ascorbic acid.
barium carbonate BaCO3 ----- Difficult to find. Sometimes available from pottery and ceramic supply stores.
barium sulfate BaSO4 Lithopone Available from fine art supply houses in a compound with zinc oxide.  This compound is known as "Lithipone" pigment. Also available in very pure form from radiology labs and medical supply as a radio contrast agent for x-rays and CAT scans. May be available from a well-stocked pottery and ceramics supply store.
benzoyl peroxide C14H10O4 benzoic acid peroxide Concentrations as high as 10% are available in the US at drug stores in cream form for treatment of acne. A paste containing 50% benzoyl peroxide, is available from some hardware stores under the brand name "Minwax High Performance Wood Filler."
bismuth Bi Lead-free shot/sinkers Available as a non-toxic lead replacement for bullets, shot, and fishing sinkers. Unfortunately, not as inexpensive as lead. Also, when sold as a lead replacement it is generally alloyed with tin. Note that to make bismuth crystals you will need very pure bismuth metal.
bismuth subsalicylate C7H5BiO4 Pepto-bismol The active ingredient in Pepto-bismol and Kaopectate.
boric acid H3BO3 Ant/Roach Killer This insecticide is found in most grocery or hardware stores. Look in the pest control section.
bromthymol blue C27H28Br2O5S pH Test Aquarium pH test kits often employ bromthymol blue because it changes color in the 6.0-7.6 range.
butane C4H10 Butane The lighter fluid in hand-held fire starters or cigarette lighters is usually liquid butane. Also available in sporting goods & camping stores as a stove fuel. Many similar fuels use propane, so be sure to read the labeling.
caffeine C8H10N4O2 No-Doz Grocery or drug store. Often in formulation with corn starch as a binder.
cadmium sulfide CdS Cadmium Yellow Fine art supply house.  Available as a yellow powder.  Sometimes pure, sometimes blended with zinc sulfide to create alternate hues.
calcium carbide CaC2 ----- Still used by cavers and spelunkers to generate acetylene gas for miner's lamps.  May be found through a local caver organization (grotto) or at some non-chain camping/outdoor supply stores.
calcium carbonate CaCO3 Limestone, Carbonate of Lime Chalk, limestone and marble chips are good sources of solid calcium carbonate; some antacids are largely calcium carbonate.  Available as a fine powder used as an extender in paint making from fine art supply stores.  Often called "Marble Dust" or "Precipitated Chalk.".
calcium chloride CaCl2 Road Salt/De-Icer Much of the road salt (de-icer) used to de-ice roads in cold climates is calcium chloride. Sometimes available as a water hardening agent at swimming pool supply stores.
calcium hydroxide Ca(OH)2 Slaked Lime It is used in lime-softening water treatment and in plastering.  Can be easily made from lime or quicklime by adding water to create slaked lime .  It can also be made by dissolving calcium chloride with sodium hydroxide in water.
calcium hypochlorite Ca(ClO)2 ----- Bleaching powder and some swimming pool disinfectants contain calcium hypochlorite. Available from cleaning or swimming pool supply companies.  Keep in mind that some formulations contain cyanuric acid as a stabilizer against UV light.
calcium nitrate Ca(NO3)2.4H2O Norwegian saltpeter Available from garden supply and agricultural supply stores as a fertilizer.
calcium oxide CaO Lime, Quicklime Used to make plaster. It is now difficult to obtain from hardware stores. Can be made by heating calcium carbonate at very high temperatures (> 900C).
calcium phosphate, monobasic Ca(H2PO4)2 Superphosphate Available as a fertilizer from garden supply stores.  Also sometimes available as a nutritional supplement at health food stores.
calcium sulfate, anhydrous CaSO4 ----- Can be made from commonly available plaster of paris by additional heating to above 180C.  Also available at fine art supply stores as Terra Alba.
calcium sulfate, hemihydrate CaSO4 . 1/2H20 Plaster of Paris Easily available in hardware stores, arts and craft stores, and hobby shops.
calcium sulfate, dihydrate CaSO4 . 2H20 Gypsum Can be made from the reaction of Plaster of Paris with Water.
camphor C10H16O ----- Can be found as a flavor additive at some Chinese grocery stores.  Sometimes found in the drugstore as a cream or oral remedy.  It feels cool like menthol on the skin.
carbon C Soot Charcoal briquettes used in cooking are available at the grocery store but contain a variety of additives.  Activated charcoal used in fish tank filters and graphite used in pencil leads are good sources of carbon. Lamp Black artists pigment is pure carbon in a fine powder and is available from fine art supply stores. The anodes in carbon-zinc (heavy-duty) batteries are pure carbon. Coal is not a good source for carbon due to a wide number of impurities and varying grades. Brazing or Gouging rods are available from welding supply stores and are composed of graphite. Graphite is also available as a common lubricant from hardware stores.
carbon dioxide CO2 ----- Dry ice is available from party stores, supermarkets, refrigeration supply companies and ice cream companies.  Nationally distributed by Airgas through "Penguin Brand Dry Ice."  Gaseous form available in small canisters at sporting goods stores.  Used in air guns and in paintball.
carbonic acid H2CO3 ----- Soda water is simply carbonated water, a dilute solution of carbonic acid.  A "Soda Club" home soda maker is a good way to make your own carbonic acid in varying strengths.
carrageenan ----- ----- Available in some health food stores as a food additive.  Used in many commercial food preparations as a thickener and gelling agent.  Available at fine art supply stores for use in molding.
cellulose (C6H10O5) n ----- Processed cotton fiber is almost pure cellulose making many undyed clothing articles an excellent source of cellulose. 100% cotton paper is also a good source of this material.
chromium oxide CrO3 Chromium Green Used as a green pigment for fine art paints.  It is available as a powder from most fine art supply stores.
citric acid C6H8O7 Sour Salt Available at the grocery store as "Sour Salt."  Also used for home soap making and also in photographic development.
copper Cu ----- Electrical wire, copper pipe, and copper sheeting are available at hardware stores and are almost 100% pure copper.  American pennies (minted 1944-1946, 1962-1982) are 95% copper and 5% zinc.  Pennies minted after 1982 are only copper clad.
copper naphthenate Cu(C11H10O2)2 cupric naphthenate Used as a wood preservative to protect lumber from termites, ants, and other burrowing insects. Brands including Wolman and Jasco are up to 25% copper naphthenate with the remainder composed of linseed oil and petroleum distillate-based solvents.
copper sulfate CuSO4 ----- Available from garden supply or pond supply stores as an algaecide and rootkiller. Note that blue vitriol is copper sulfate pentahydrate and can be converted into unhydrated copper sulfate by heating to 150C until it turns pure white.
copper sulfate pentahydrate CuSO25H2O ----- Fairly easy to obtain.  It is the active ingredient in many algaecides used to kill algae and other aquatic pests.  Available for pest control at many gardening and agricultural supply stores as a root killer.
cyanuric acid C3H3N3O3 isocyanuric acid Available from swimming pool and lawn/yard supply stores as a chlorine stabilizer. A pure tablet form sells under the brand name "Kem Tek."
dextrose C6H12O6 glucose Dextrose (glucose) is available in many grocery and drug stores. Some throat lozenges are pure dextrose. Dextrose is right-handed (dextrorotatory) glucose. Levulose is left-handed (levorotatory) glucose. Most products are a half-and-half mix.
dichloromethane CH2Cl2 methylene chloride Used as a solvent, degreaser and adhesive remover, it is available from hardware, automotive, and sometimes craft stores. Purity of commercial products can approach 90% with the remainder being composed of alcohols and petroleum distillates. Common brands include "Champion Paint Off," many choke and valve cleaners, and Klean Strip Grafitti Remover.
dimethyl Sulfoxane (CH3)2SO DMSO Available from health food and naturopathic supply stores for treating injuries. Warning: DMSO will allow anything it has dissolved to pass directly through your skin into your bloodstream. Use gloves and skin protection when working with this chemical.
ethanol/ethyl alcohol C2H5OH Everclear Available as 95% pure ethanol and 5% water from liquor stores in most states. Also available in denatured form from hardware stores. Grocery and drug stores may it as carry ethyl rubbing alcohol.
ether (C2H5)2O diethyl ether, ethoxyethane Sold at auto supply stores in aerosol cans as "Starter Fluid" or "Cold Start Spray." Used to help start damp or inefficient old engines.
ethylene glycol CH2OHCH2OH 1,2 ethanediol Some engine antifreezes are primarily ethylene glycol and can be obtained at an automotive supply store.
eugenol CH2CH2CH2C6H3(OCH 3)OH oil of clove, 2-methoxy-4-(2-propenyl)phenol Available at most health food and natural healing stores as clove oil. Note that organically derived oil of clove will have numerous impurities from the distillation process. Synthetic oil of clove is generally pure but more difficult to find.
formic acid ----- methanoic acid Available in some stain removers at the hardware store. A fairly pure 5% concentration can be obtained from the blue chamber of "Clorox Dual Action Toilet Bowl Cleanser."
fructose C6H12O6 Fruit Sugar Easily available from most grocery stores.
glucose C6H12O6 Dextrose Dextrose (glucose) is available in many grocery and drug stores. Some throat lozenges are pure dextrose. Dextrose is right-handed (dextrorotatory) glucose. Levulose is left-handed (levorotatory) glucose. Most products are a half-and-half mix.
glycerin, glycerol C3H8O3 1,2,3 propanetriol Glycerin is an emollient used to soften skin by delaying the evaporation of water. It is available at most drug stores.
gold Au ----- Gold jewelry is generally not pure gold. Gold is generally alloyed with other metals to increase strength.  Gold coins are often .999 fine gold and many may be obtained at "bullion value" from local coin shops.  Pure gold dust and gold foils are available from fine art supply stores.
gum arabic n/a gum acacia Available from most craft and fine art supply stores in solution with water.
helium He ----- Helium can be obtained from party stores or wherever helium balloons are available.  Small disposable containers are available for long-term storage. Containers made by Worthington Industries are 99% pure helium. Note that "balloon gas" is a mixture of helium and normal air.
hexamine C6H12N4 Hexamethylenetetramine Sold as solid fuel tablets in camping and outdoor stores.
hydrogen gas H2 Hydrogen Can be generated and captured from electrolysis of water and a wide variety of inorganic chemical reactions.  Adding aluminum foil to a solution of Sodium Hydroxide will generate hydrogen gas.  Highly flammable and explosive under pressure or in quantity.
hydrochloric acid HCl Masonry Cleaner Muriatic acid (the common name for HCl) is used in swimming pool maintenance. It is also sold as masonry cleaner and is available at the hardware store. Percentages vary but concentrations as high as 35% can be found easily.
hydrofluoric acid HF Glass Etching Solution Available at some hardware stores and at most fine art supply houses for etching glass.  Available in some grocery stores under various brand names as a rust remover. It is highly recommended that you keep Calcium Gluconate gel on hand in case of an accidental spill. Highly toxic and dangerous.
hypochlorous acid HClO Laundry Bleach Grocery store.
hydroquinone C6H6O2 ----- Photography store catering to the at-home darkroom crowd.
hydrogen peroxide H2O2 Peroxide Hydrogen peroxide antiseptic (3%) is available from the drug store. Clairoxide hair bleach by Clairol is much more concentrated (12%) and is available from beauty supply stores.  Concentrations as high as 35% may be available at health food stores and natural medicine stores as a source of "natural oxygen." Swimming pool and spa suppliers often carry concentrations as high as 27% but these usually contain preservatives/stabilizers. Note: Do not heat. Do not store in metal containers.
iodine I2 Iodide Tincture of iodine, a topical antiseptic used for treating wounds, is a solution of iodine dissolved in ethyl alcohol. It is available at most drug stores. Available from camping stores as crystals for sterilizing water.
iron Fe ----- Steel wool, iron nails, iron bolts, nuts, screws are good sources of iron. You can get iron filings by dragging a strong magnet through sand or iron-fortified breakfast cereals.
ferric chloride FeCl3 Etching Solution Available in solution from Radio Shack and other electronics suppliers as an etching solution for circuit boards.  Also available in solution from fine art supply stores.
ferric oxide (Iron III Oxide) Fe2O3 Rust Common rust.  Reddish in color.  Can be scraped off of rusted iron objects or purchased in a purified form as the artists pigment "Red Iron Oxide" from fine art supply stores.  

ferrous ferric oxide
(Iron II III Oxide)

Fe3O4 Magnetite Used as the artists pigment "Mars Black" and can be purchased from fine art supply stores.

Iron Sulfate

FeSO4 Ferrous Sulfate, Sulfate of Iron Available from garden supply stores as a nutrient. Also available as a mordant for pigments from stores which carry dyeing and textile supplies.
gum arabic ----- ----- Available at arts & crafts stores and at fine art supply stores as a binder for turning pigments into paints.
kerosene CnH2n+1 (n=12-16) Aviation Fuel Lamp oil or kerosene is sold in the paint departments of most hardware stores.  Also available in larger quantities from gas stations in many parts of the country.
lactic acid C 3 H 6 O 3 Milk Acid Available from grocery stores and health food stores.
latex C3H6O3 Liquid Latex Body Paint Available from adult toy stores as a novelty item and from select hobby shops.  Compositions vary in the amount of ammonia and fillers they contain.
linseed oil ----- ----- Used as a binder in paints and as a finish for wood.  Available at hardware stores and fine art supply stores.
lead Pb ----- Lead shot and lead sinkers are used by fishermen and are available at sporting goods stores. They may be alloyed with tin and antimony. Also lead is used for wheel balancing weights at auto garages. Lead sheeting may be obtained from stores that carry roofing supplies.
magnesium Mg Fire starter Sold in solid blocks as a fire starter in many camping and outdoor stores.
magnesium carbonate MgCO3 Athlete's chalk Often sold as a powder in sporting goods stores for gymnastics, weightlifting, and climbing to help keep hands dry.  Sometimes it is combined with calcium carbonate in this use. Available in tablet form as an antacid. Some antacids are pure while others are blended with calcium carbonate.
magnesium hydroxide Mg(OH)2 Milk of Magnesia Milk of Magnesia is an antacid used to settle sour (acidic) stomachs. Some antacid tablets also contain magnesium hydroxide.
magnesium silicate Mg3Si4O10(OH)2 Talc Talcum powder comes from talc, the softest of all minerals, and is used as a dusting powder for babies. It is available in the body care section of the drug store.
magnesium sulfate MgSO47H2O Epsom Salt Epsom salt is sold at most drug stores and is used as a laxative or as an anti-inflammatory soak.  Also available as a chemical for photographic development.
manganese dioxide MnO2 ----- Available as the black powder in unused alkaline or carbon-zinc batteries. By extensively washing this powder in distilled water you can remove the embedded Zinc Chloride solution.
mercury Hg quicksilver Becoming difficult to find due to fears of toxicity and environmental contamination.  Old mercury switches can be found in many thermostats.  Old-style thermometers contain mercury.  Fluorescent light tubes contain a small amount of mercury though it can be difficult to extract. Specialty occult stores may carry it as quicksilver.
methane CH4 Natural Gas Gas line in many homes.
methanol CH3OH Methyl Alcohol Methanol is sold as a solvent in paint supply stores under the names "wood alcohol" or "methyl alcohol."  Available from automotive supply as a gasoline line anti-freeze.
methyl ethyl ketone CH3COC2H5 MEK Available from most hardware stores as a solvent.
methyl ethyl ketone peroxide C8H16O4 MEKP Available in dilute solution from hardware and boating supply stores as a catalyst for the polymerization of polyester resins.
methylene blue C16H18ClN3S Methidote Methylene blue (Methidote antiseptic) is used to treat small injured fish and is available at pet stores.
methylene chloride CH2Cl2 dichloromethane Used as a solvent, degreaser and adhesive remover, it is available from hardware, automotive, and sometimes craft stores. Purity of commercial products can approach 90% with the remainder being composed of alcohols and petroleum distillates. Common brands include "Champion Paint Off,", many choke and valve cleaners, and Klean Strip Grafitti Remover.
methyl salicylate C6H4(OH)COOCH3 Oil of Wintergreen Drug Store
mineral oil complex mixture of hydrocarbons ----- Mineral oil is sold in drug stores as an emollient. Some baby oils are essentially mineral oil and fragrance.
naphthalene C10H8 moth balls Hardware store or grocery store.
nickel Ni ----- Pre-1985 Canadian nickels are made of nickel. Note: American "nickels" are composed of 25% nickel and 75% copper. Nickel is often used as a welding filler material, and 1/16-1/8" Ni wire is often available at welding supply stores.
nitrogen N2 liquid nitrogen Hospital, laboratory, university, welding supply house, and industrial gas supplier can all provide liquid or gaseous nitrogen.
nitrous oxide N2O whipping gas Whipped cream canisters from the grocery store. Or in larger canisters from commercial restaurant supply houses.  When packaged for automotive use it is usually contaminated with hydrogen sulfide to discourage inhalation.
oxalic acid C2H2O4 rust remover Radiator cleaner from drug or hardware store.  Also available in the hardware store as "wood bleach powder." Auto supply stores carry it as a rust remover as well. "Prestone Heavy Duty Cooling System Cleaner" may contain up to 98% oxalic acid with handful of trace, and mostly inert, impurities.
oxygen O2 ----- Portable welding oxygen tanks are available at welding shops and some hardware stores.  Can be generated in small quantities from the electrolysis of water.
para-dichlorobenzene C6H4Cl2 moth flakes, moth crystals Hardware or grocery store.
paraffin CnH2n+2 (n>19) ----- Unless otherwise labeled, candle wax is made of paraffin. Some grocery stores sell paraffin as a sealant for home canning.  Many arts and crafts stores sell paraffin for at-home candle makers. "Vaseline" brand is also paraffin, albeit with molecules that are slightly shorter.
phenolphthalein C20H14O4 ----- Magic shops might carry it as a pinkish disappearing ink.  Blue disappearing ink is not phenolphthalein.  Difficult to find outside of chemical supply.
phenol red C19 H19SO5 phenolsulfonephthalein Used as a pH tester for swimming pools.  Available at swimming pool supply stores.
phosphoric acid H3PO4 pH Down Some pH reducers (available at pet stores) used in fish tanks are simply dilute solutions (up to 30%) of phosphoric acid.  Also available in gel form at hardware stores as a rust remover.  "Naval Jelly" in a spray bottle at hardware stores.  Also used as a solder flux.
polystyrene casting resin ----- Hobby shop
polyurethane foam ----- Mountains in Minutes Hobby shop, hardware, or  building supply store.
potassium aluminum sulfate KAl(SO4)212H2O Alum, aluminum potassium sulfate It is used as an astringent to shrink mucus membranes.  Some styptic pencils use it in their formulation. Often sold as a deodorant stone at natural health stores.  Also available as a mordant for clothing dyes (RIT brand and others).
potassium bitartrate KHC4H4O6 Cream of Tartar Cream of Tartar is available at the grocery store and is used to stabilize delicate foods like meringue toppings and other baked egg-white products.
potassium carbonate K2CO3 Potash Available at some garden supply and agricultural stores.
potassium bromide KBr ----- Photography store catering to the at-home darkroom crowd.
potassium chloride KCl Salt Substitute Available as a salt substitute by people who must limit their sodium intake, and is available at most supermarkets.  Also available in larger, though slightly less pure, quantities as a road salt de-icer.
potassium chromium sulfate KCr(SO4)2*12H20 potassium chrome alum Photography store catering to the at-home darkroom crowd.
potassium dichromate K2Cr2O7 ----- Photography store catering to the at-home darkroom crowd. Also used as a mordant ("Chrome Mordant") for textiles and may be available at a dyeing and fabric store.
potassium iron (ii) hexacyanoferrate(iii) KFe[Fe(CN)6] potassium iron ferricyanide or potassium ferroferricyanide Mrs. Stewart's liquid laundry bluing is used to whiten clothes and may be found in the detergents section of the supermarket.
potassium hydroxide KOH Caustic Potash Available at some ceramic supply houses and from arts and crafts stores for soap making.  Difficult to find.  May be the active ingredient in some drain cleaning solutions.  Kodak SII Activator is 10% Potassium Hydroxide with various sulfites and bromides in the mixture.  Veterinary supply houses may carry it for dissolving hair and horns in animals.
potassium iodide KI Radiation Pills Available sometimes as a photographic development chemical.  Also from outdoor/survivalist stores in pill form to avoid the uptake of radioactive iodine during a nuclear accident.
potassium metabisulfite K2S3O5 Campden powder Used as a sterilizing agent in winemaking and brewing processes. Sold as tablets which may be pure, blended with sodium metabisulfite, or contain only sodium metabisulfite.
potassium nitrate KNO3 Saltpeter Saltpeter or quick salt is used to cure home made sausages and corned beef and may be available at independent butcher shops. Also available from agriculture and gardening stores as a root killer.
potassium permanganate KMnO4 Clearwater Clearwater is a solution of approximately 50% potassium permanganate and is used to remove odors and cloudiness from water to be used in aquariums and garden ponds.
propane C3H8 ----- Gas barbecue fuel is generally made of propane and is available at many gasoline stations or picnic supply stores.
2-propanol CH3CHOHCH3 Rubbing Alcohol Rubbing alcohol (isopropyl alcohol) is a concentrated solution of 2-propanol and may be found in most drug stores.  Supermarkets owned by Safeway carry a 99% pure version.
silicon Si2 ----- Fairly pure silicon crystal can be found as one of the rock varieties in many "fill your bag with treasure" stands at tourist-oriented gift shops.
silicon carbide SiC2 Carborundum This hard, abrasive powder is often found sorted by particle size for use in sandblasting and industrial supply houses.
silicon dioxide SiO2 Sand Quartz sand is relatively pure silicon dioxide and is available at many building supply stores and also aquarium shops. Often found sorted by particle size for use in sandblasting. Micron sized particles are used as a filler in rubbers, plastics, and mold making materials and may be available in hobby shops as Min-u-Sil brand. Available in a porous, amorphous form as the silica desiccant packets found in many sealed food envelopes, electronics boxes, and other packaging. New desiccant packets are often available from local photography stores which cater to the at-home darkroom crowd. Non-porous amorphous silica is industrially known as Cab-o-Sil.
silver Ag ----- Older non-clad American dimes, quarters, half dollars and silver dollars are 90% silver and 10% copper. Pure silver coins and bullion can be obtained from local coin shops, often at bullion value.
sodium acetate NaC2H3O2 Hand Warmer Main ingredient in hand-warmers that are available at sporting goods stores.  Can also be made through the reaction of baking soda and vinegar.
sodium borate Na2B4O710H2O ----- The water can be driven off of grocery store Borax by heating to 200C to create pure sodium borate (although it will begin absorbing atmospheric moisture again when cooled and left in the open).
sodium bicarbonate NaHCO3 Baking Soda, Bicarbonate of Soda Baking soda is pure sodium bicarbonate and may be found in the baking section of the grocery store.
sodium biphosphate Na2HPO4 pH Down Found at pet stores and used to lower the pH of aquarium water.
sodium bisulphate NaHSO4 pH Down Pool supply store
sodium bromide NaBr Hot Tub Salt Pool supply store
sodium carbonate Na2CO3 Washing Soda Washing soda is used to treat wool fibers and is available at spinning, weaving, and art supply stores.  It is also available in most grocery stores and supermarkets under the Arm & Hammer brand.
sodium chlorate NaClO3 ----- Available from gardening and agricultural stores. This herbicide is toxic to all green plants and, as such, is becoming less available as more selective herbicides some onto the market. Some brand names are Atlacide, Defol, Drop-Leaf, and Tumbleaf. Read product labeling to deduce the particular purity of any of these brands.
sodium chloride NaCl Salt The table salt used in cooking is sodium chloride. Iodized salt contains traces of sodium iodide.  Uniodized salt is available and is often explicitly labeled as such. Table salt also usually contains anti-caking agents such as magnesium carbonate. Kosher salt, canning salt, or other large crystal salt is generally more pure. For larger quantities, uniodized sodium chloride can be obtained inexpensively from water softener suppliers.
sodium fluoride NaF ----- Used in toothpastes and mouthwashes to prevent cavities. Difficult to obtain in pure form. Most dental solutions contain a laundry list of inert ingredients to provide coloring, flavor, foaming, and other aesthetic properties.
sodium hexametaphosphate (NaPO3)6 Sodium polymetaphosphate, Calgon water softener This water softener, surfactant and detergent is the primary ingredient in Calgon water softener. It is available at the grocery and hardware store. It is also known by other names including: glassy sodium, Graham's Salt, and hexasodium salt.
sodium hydroxide NaOH Lye/Caustic Soda Known also as caustic soda and lye, sodium hydroxide is used in many commercial drain cleaners/openers.  Available in markets,