Group VA (15) Elements - Nitrogen Family

GROUP VA (15) ELEMENTS – NITROGEN FAMILY MEMBERS: Nitrogen – N Phosphorus – P Arsenic – As Antimony – Sb Bismuth – Bi • Old Name: Phictogen (nitrogen’s property to cause choking/coughing in the absence of air) • oxides of N & P are acidic • oxides of As & Sb are amphoteric • oxide of Bi is basic Cyanide (CN) - MOA: inhibits cytochrome oxidase (ETC) Source: cassava, Na nitroprusside Treatment: 1. NaNO2/Amylnitrite MOA: methemoglobinemia 2. Sodium thiosulfate MOA: CN to thiocyanate 3. Methylene blue MOA: methemoglobinemia A. NITROGEN (N) (Mephitic air, azote, without life) o Most abundant gas in air: 71% N2, 29% O2 o • 78.09% of Earth’s atmosphere o • most abundant gas in the air (atmosphere; followed by O) o • prepared by fractional distillation of liquid air o • essential nutrient of plant and animal tissues, in proteins & amino acids o • most stable diatomic molecule (N2) o • nitrates & other nitrogen compounds used as fertilizers (NPK) & explosives o • Nitrogen gas: inert atmosphere for oxidizable pharmaceuticals (substitute: Argon) o • Liquid Nitrogen: refrigerant (cryogenic preservation- process of cooling and storing cells, tissues, or organs at very low or freezing temperatures to save them for future use) o MOT of Nitrites & Nitrates: nitrites are potent oxidizing agents & cause methemoglobinemia (ferrihemoglobin) o ANTIDOTE: 1% methylene blue (accelerates enzymatic reduction of metHB) Nitrogen, NF N2 Cont: BLACK Azote “mephitic air” ; colorless and odorless gas • very stable because of 3 covalent bonds • USE: diluent for oxygen for deep sea diving purposes but can cause bends; decompression sickness, injuries caused by a rapid decrease in the pressure that surrounds a diver, causing formation of bubbles in tissues & blood. (replaced by He) • INERT ATMOSPHERE • Liquid nitrogen – refrigerant Nitrous Oxide N2O Cont: BLUE Laughing Gas, Nitrogen monoxide, Dinitrogen monoxide • weakest but probably the safest general anesthetic and as dental Anesthetic; least potent inhalational anesthetic • SE: diffusion hypoxia (Following discontinuation of nitrous oxide, the concentration gradient between the gases in the lung and alveolar circulation rapidly reverses.) • Inhalational anesthetic (general) Nitric Oxide NO • causes vasodilation • an important endogenous NT produced by neurons and other cells • associated with the mechanism of drugs like Sildenafil & Nitroglycerin (nitric oxide-mediated vasodilation • Vasodilator, For CN poisoning Nitrite (NO2 - ) • vasodilator; (also nitrate) used as antidote for CN poisoning (have high affinity to CN) • forms red color with Giess-Ilosvay Test (sulfanilic acid- 1-naphthylamine reagent) Nitrate (NO3 - ) • preservative • ion when warmed with concentrated sulfuric acid & metallic Cu, evolved brown gas: (+) results with Brown Ring Test; & no visible reaction w/ diluted sulfuric acid • gives white crystalline precipitate w/ the presence of Nitron Reagent (diphenyl-endo-anilodihydrotriazole) *Lunge Test – most sensitive test for nitrate *Pentaerythritol Tetranitrate – longest acting nitrate Nitric Acid, NF HNO3 Spirit of Nitre, Aqua Fortis/Fuerte/Eau Forte • an aqueous solution containing not less than 69% & not more than 71% by weight of HNO3 B. PHOSPHORUS (P) (light carrier, St. Elmo’s Fire) Allotropes of P:  Scarlet  Violet  Metallic/Black  Red o o o o o o o - tribromide ∆240°C with Hg - white ∆200°C with Na - 530° with Pb - white + chromic acid • 11th most abundant element in Earth’s Crust • essential for life, both as structural material in higher animals & essential in metabolism of both plants & animals • Occurs as phosphate in the body [PhIClO] • TOXICITY: may cause severe burns and chronic poisoning may cause bony necrosis, especially of mandible; “Phossy Jaw” • USES: antacids; cathartics White/yellow (poisonous), Red (non-poisonous) • TWO FORMS:  a. Red Phosphorus  - non-poisonous & non-flammable in air, except at high temperature; less active form of phosphorus.  - formed when White P is heated to 250°C or at a lower temp in the presence of sunlight.  b. White Phosphorus or Yellow Phosphorus  - phosphorescence: when exposed to air in the dark, it emits greenish light & gives off White Fumes (exothermic) with garlic odor  - has distinctive, disagreeable, ozone-like odor  - toxic / poisonous form of phosphorus • ALLOTROPIC MODIFICATIONS:  a) Black/Metallic P (white P w/ Pb @ 500-530°C under high pressure); most stable allotrope of P o  b) Scarlet P (PbBr with Hg @ 240°C); used in match industry  c) Violet P (white P w/ Na @ 200°C under very high pressure) CuSO4 Phosphate PO4 • USE: antacids; cathartics • insoluble phosphates: Mg ; Sr ; Ba ; Ca Phosphoric Acid, NF H3PO4 • used to form soluble salts of insoluble medicinal base (Orthophosphoric Acid) Hypophosphorous Acid PH2O2 • used as an antioxidant in Hydroiodic Acid Syrup & Ferrous Iodide Syrup • powerful reducing agent C. ARSENIC (As) (Lewisite Metal) o o o o o o o o • component of Salvarsan (Antisyphilis)/ Arsphenamine • binds to –SH (keratin of nails & hair) • Identification Test: Gutzeit’s Test (modified version of Marsh Test) Protoplasmic poison Insecticide: Copper Aceto Arsenate (Paris green) Mee’s Line | BAL (British Anti Lewisite) First anti-syphilis (Paul Ehrlich) – Arsphenamine/Salvarsan/Magic bullet/Compound 606 • Chemistry  – Trivalent Arsenic (Arsenous ion)  • more toxic; most common form of As  • in combination with halides, it is present as cation  • Inorganic arsenic toxicity; trivalent is more acutely toxic than pentavalent As  Pentavalent Arsenic (Arsenic ion)      • Common; veterinary anthelmintics and treatment of amoebiasis and trypanosomiasis (potent trypanoside) • Organic arsenic toxicity; pentavalent are less toxic than trivalent organoarsenic and inorganic As • Acute Poisoning: Aldrich-mees lines (transverse) whiter straying in the nails • Chronic Poisoning: “Rain-drop” hyperpigmentation of the torso and extremities • ANTIDOTES:  1st line: Unithiol (DMPS- Dimercaprol Propane Sulfonic Acid) – a water-soluble analog of BAL that is best for acute arsenic poisoning.  2nd line: Dimercaprol/BAL; chelating agent of 2nd choice is Unithiol is not available.  3rd line: Oral Unithiol or Oral Succimer: once patient is stable.  Arsenic is usually alloyed with Pb to make it harder; doping semiconductors and light emitting diodes 1. A r s e n i c T r i o x i d e As2O3 - Insecticide, Anti-leukemic • Trisenox® (old brand) - was reintroduced to USP for treatment of leukemia (given IV together with tretinoin) • primary standard for Ce(SO4)2 • used as rat & ant poison; wood preservative to prevent wood rot • used in preparation of Paris Green; Fowler’s Solution; Donovan’s Solution