Physical Properties
Colorless orthorhombic crystals or white powder; converts to cubic form at 316°C; density 8.445 g/cm3 (orthorhombic form) and 7.750 g/cm3 (cubic form); melts at 855°C; vaporizes at 1,290°C; slightly soluble in water (640 mg/L at 20°C); KSP 7.12x10–7 at 25°C; soluble in nitric acid; insoluble in acetone and ammonia.
Uses
Lead difluoride is used in low melting glasses; in glass coatings to reflect infrared rays; in phosphors for television-tube screens; for nickel plating on glass; and as a catalyst for the manufacture of picoline.
Preparation
Lead difluoride can be prepared by several methods. It is obtained by treating lead hydroxide or lead carbonate with hydrofluoric acid, followed by evaporation of the solution:
Pb(OH)2 + 2HF → PbF2 + 2H2O
Alternatively, it is precipitated by adding hydrofluoric acid to a lead(II) salt solution; or adding potassium fluoride to lead nitrate solution:
2KF + Pb(NO3)2 → PbF2 + 2KNO3
Lead difluoride also can be directly synthesized from its elements, by the action of lead with fluorine.
Toxicity
Slightly to moderately toxic by ingestion and subcutaneous routes. The oral LD50 in rats is around 3,000 mg/kg.
Description
Lead fluoride is a white to colorless, odorlesscrystalline (rhombic, orthorhombic) solid. Molecularweight =245.19; Boiling point=1292℃; Freezing/Meltingpoint = 825℃. Hazard Identification (based on NFPA-704M Rating System): Health 1, Flammability 0, Reactivity 0.Slightly soluble in water.
Chemical Properties
Lead fluoride is a white to colorless, odorless
crystalline (rhombic, orthorhombic) solid
Uses
Lead(II) fluoride is used in fuses, glass coatings to reflect infrared rays and phosphors for television screens and in low melting glasses. Further, it serves as a catalyst for the preparation of picoline.
Application
It is used as the transmission window in λ: 250 nm–10 mm and as the prism in the infrared region.
General Description
Odorless white solid. Sinks in water.
Reactivity Profile
Calcium carbide mixed with Lead fluoride , at ordinary temperatures, becomes incandescent [Mellor 5:862-64. 1946-47].
Health Hazard
Not irritating to skin or mucuous membranes; protect against chronic poisoning. Early symptoms of lead intoxication via inhalation or ingestion are most commonly gastrointestinal disorders, colic, constipation, etc.; weakness, which may go on to paralysis chiefly of the extensor muscles of the wrists and less often the ankles, is noticeable in the most serious cases. Ingestion of a large amount causes local irritation of the alimentary tract; pain, leg cramps, muscle weakness, paresthesias, depression, coma, and death may follow in 1 or 2 days. Contact with eyes causes irritation.
Fire Hazard
Non-combustible, substance itself does not burn but may decompose upon heating to produce corrosive and/or toxic fumes. Some are oxidizers and may ignite combustibles (wood, paper, oil, clothing, etc.). Contact with metals may evolve flammable hydrogen gas. Containers may explode when heated.
Potential Exposure
Used to make other chemicals, underwater paints; electronic and optical parts (for growing
single-crystal, solid-state lasers); in high-temperature dryfilm lubricants; and making special grades of glass.
First aid
If this chemical gets into the eyes, remove anycontact lenses at once and irrigate immediately for at least15 min, occasionally lifting upper and lower lids. Seek medical attention immediately. If this chemical contacts theskin, remove contaminated clothing and wash immediatelywith soap and water. Seek medical attention immediately. Ifthis chemical has been inhaled, remove from exposure,begin rescue breathing (using universal precautions, including resuscitation mask) if breathing has stopped and CPR ifheart action has stopped. Transfer promptly to a medicalfacility. When this chemical has been swallowed, get medical attention. Give large quantities of water and inducevomiting. Do not make an unconscious person vomit.Note to physician: Administer saline cathartic and anenema. For relief of colic, administer antispasmodic (calcium gluconate, atropine, papaverine). Consider morphinesulfate for severe pain.Whole blood lead levels, circulating plasma/erythrocytelead concentration ratio, urine ALA, and erythrocyte protoporphyrin fluorescent microscopy may all be useful in monitoring or assessing lead exposure. Chelating agents, such as edetate disodium calcium (Ca EDTA) and penicillamine(not penicillin), are generally useful in the therapy of acutelead intoxication.Antidotes and special procedures for lead: Persons with significant lead poisoning are sometimes treated with CaEDTA while hospitalized. This “chelating” drug causes arush of lead from the body organs into the blood and kidneys, and thus has its own hazards, and must be administered only by highly experienced medical personnel undercontrolled conditions and careful observation. Ca EDTA orsimilar drugs should never be used to prevent poisoningwhile exposure continues or without strict exposure control,as severe kidney damage can result.
storage
Color Code—Blue: Health Hazard/Poison: Storein a secure poison location. Prior to working with thischemical you should be trained on its proper handling andstorage. Store in tightly closed containers in a cool, wellventilated area. Lead is regulated by an OSHA Standard1910.1025. All requirements of the standard must befollowed.
Shipping
UN3288 Toxic solids, inorganic, n.o.s., Hazard
Class: 6.1; Labels: 6.1-Poisonous materials, Technical
Name Required. UN2291 Lead compounds, soluble n.o.s.,
Hazard Class: 6.1; Labels: 6.1-Poisonous materials,
Technical Name Required
Incompatibilities
Violent reaction with oxidizers, chemically active metals; calcium carbide. May ignite combustibles, such as wood, paper, oil, etc
