Sodium arsenite

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Sodium arsenite
Sodium-catena-arsenite-NaAsO2-xtal-2004-3D-balls.png
Identifiers
CAS number 7784-46-5 YesY
PubChem 443495
KEGG C11906 N
Jmol-3D images Image 1
Properties
Molecular formula NaAsO2
Molar mass 129.911 g/mol
Appearance white or grayish powder
Density 1.87 g/cm 3
Solubility in water soluble in water
Solubility slightly soluble in alcohol
Hazards
MSDS [3]
R-phrases R23,R25,R45
NFPA 704
Flammability code 0: Will not burn. E.g., water Health code 3: Short exposure could cause serious temporary or residual injury. E.g., chlorine gas Reactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g., liquid nitrogen Special hazards (white): no codeNFPA 704 four-colored diamond
LD50 100 mg/kg (rat, oral)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
 N (verify) (what is: YesY/N?)
Infobox references

Sodium arsenite refers to one of two compounds: sodium meta-arsenite (NaAsO2) or sodium ortho-arsenite (Na3AsO3). It is the sodium salt of arsenous acid. The solid consists of sodium cations, Na+, and catena-arsenite anions, [AsO2]n
n
, which are infinite -O-As(=O)- chains.

Catena-arsenite chains

Synthesis[edit]

A mixture of sodium meta-arsenite and sodium ortho-arsenite is produced by dissolving arsenic trioxide in a solution of sodium carbonate or sodium hydroxide and boiling. Alternatively, it can be created by a controlled interaction of caustic soda with arsenic trioxide. AsO4 can be boiled with any alkali hydroxide to produce alkali arsenite.

Structure[edit]

Sodium Arsenite exists either as an amorphous, colorless powder or as a glassy mass.[1]

Health Effects[edit]

Sodium Arsenite can be inhaled or absorbed through the skin. Along with its known carcinogenic and teratogenic effects, contact with the substance can yield symptoms such as skin irritation, burns,itching, thickened skin, rash, loss of pigment, poor appetite, a metallic or garlic taste, stomach pain, nausea, vomiting, diarrhea, convulsions, decreased blood pressure, and headache. Severe acute poisoning may lead to nervous system damage resulting in weakness, poor coordination, or “pins and needles” sensations, eventual paralysis, and death.[2][3]

Health Warning[edit]

Pure arsenic is reported to be nontoxic. However since it is readily oxidized in air, and it is difficult to be sure no impurities are present, the element should be treated with caution.[4] All measures of personal protective equipment must be utilized in order to protect oneself from effects.

Lethal Dose for humans is approximately 0.1 g.[5]

Application[edit]

Primarily used as a pesticide, but has other uses such as hide preservative, antiseptic, dyeing, and soaps.[6]

Recent evidence suggests that application of sodium arsenite is an appropriate chemical stressor to induce production of heat shock proteins.[7]

Ironically, despite its carcinogenic effects, upregulation and inhibition of various enzymes in cancerous cells by sodium arsenite results in mitochondrial apoptosis, leading to remission. More treatments are proving effective with continued research of the toxin.[8]

References[edit]

  1. ^ Eagleton M. (2011). Concise Encyclopedia Chemistry. Walter de Gruyter. ISBN 3110114518. 
  2. ^ New Jersey Department of Health and Senior Services. Hazardous Substance Fact Sheet: Sodium Arsenite [1] (2013-05-01)
  3. ^ Jing J, Zheng G, Liu M, Shen X, Zhao F, Wang J, Zhang J, Huang G, Dai P, Chen Y, Chen J, Luo W, ‘’et al.’’ (2012). "Changes in the synaptic structure of hippocampal neurons and impairment of spatial memory in a rat model caused by chronic arsenite exposure". Neurotoxicology 33 (5): 1230–8. doi:10.1016/j.neuro.2012.07.003. PMID 22824511. 
  4. ^ Science Lab: Chemicals & Laboratory Equipment. Material Safety Data Sheet Sodium arsenite, powder MSDS [2] (2013-05-01)
  5. ^ Haynes W.M. (2012–2013). CRC Handbook of Chemistry and Physics, 93rd Ed. Taylor & Francis Group. ISBN 1439880492. 
  6. ^ Considine G.D. (2005). Van Nostrand’s Encylcopedia of Chemistry. 14th Ed. ISBN 0471615250. 
  7. ^ Bhagat L, Singh VP, Dawra RK, Saluja AK, ‘’et al.’’ (2008). "Sodium arsenite induces heat shock protein 70 expression and protects against secretagogue-induced trypsinogen and NF-kappaB activation". J Cell Physiol 215 (1): 37–46. doi:10.1002/jcp.21286. PMID 17941083. 
  8. ^ Ivanov VN, Hei TK, ‘’et al.’’ (2011). "Regulation of apoptosis in human melanoma and neuroblastoma cells by statins, sodium arsenite and TRAIL: a role of combined treatment versus monotherapy". Apoptosis. 16 (5): 1268–84. doi:10.1007/s10495-011-0649-2. PMID 21910007.