7784-45-4 Usage
Chemical Properties
red powder(s); enthalpy of formation ?58.2 kJ/mol; entropy 213.0 J/(mol · K); enthalpy of vaporization 59.3 kJ/mol; decomposes slowly in air at 100°C, rapidly at 200°C, to give As, I2, As2O3; made by precipitation from a hot AsCl3-HCl solution by the addition of KI [KIR78] [STR93]
Uses
Different sources of media describe the Uses of 7784-45-4 differently. You can refer to the following data:
1. Formerly the compound was used in dermatitides.
2. Arsenic(III) iodide is useful for preparing organoarsenic compounds.
Preparation
Arsenic triiodide is prepared by treating elemental arsenic with a solution of iodine in carbon disulfide. Alternatively, it can be precipitated out from a hot solution of arsenic trioxide or arsenic trisulfide in hydrochloric acid on treatment with potassium or sodium iodide. Also, it is made by the reaction of arsenic trichloride with potassium iodide.
General Description
Orange-red rhombohedral crystals (from acetone). Density 4.69 g / cm3. Melting point 285.6°F (140.9°C). Red as a liquid.
Air & Water Reactions
Reacts slowly with oxygen from the air, liberating iodine [Merck]. Water soluble. Aqueous solutions are strongly acidic (pH of 0.1N solution about 1.1) and ultimately form HI and As2O3, although an equilibrium AsI3 + 3H2O = H3AsO3 + 3HI has been observed [Merck 1989].
Reactivity Profile
ARSENIC IODIDE gives acidic solutions in water. These solutions neutralize bases exothermically. Can react as either an oxidizing agent or reducing agent.
Hazard
Toxic and carcinogen.
Fire Hazard
Combustible material: may burn but does not ignite readily. Containers may explode when heated. Runoff may pollute waterways. Substance may be transported in a molten form.
Safety Profile
Inorganic compounds
are confirmed human carcinogens
producing tumors of the mouth, esophagus,
larynx, bladder, and paranasal sinus.
Recognized carcinogens of the skin, lungs,
and liver. Used as insecticides, herbicides,
silvicides, defoliants, desiccants, and
rodenticides. Poisoning from arsenic
compounds may be acute or chronic. Acute
poisoning usually results from swallowing
arsenic compounds; chronic poisoning from
either swallowing or inhaling. Acute allergic
reactions to arsenic compounds used in
medical therapy have been fairly common,
the type and severity of reaction depending
upon the compound. Inorganic arsenicals
are more toxic than organics. Trivalent is
more toxic than pentavalent. Acute arsenic
poisoning (from ingestion) results in marked
irritation of the stomach and intestines with
nausea, vomiting, and darrhea. In severe
cases, the vomitus and stools are bloody and
the patient goes into collapse and shock
with weak, rapid pulse, cold sweats, coma,
and death. Chronic arsenic poisoning,
whether through ingestion or inhalation,
may manifest itself in many different ways.
There may be disturbances of the digestive
system such as loss of appetite, cramps,
nausea, constipation, or diarrhea. Liver
damage may occur, resulting in jaundice.
Disturbances of the blood, kidneys, and
nervous system are not infrequent. Arsenic
can cause a variety of skin abnormalities
including itching, pigmentation, and even
cancerous changes. A characteristic of
arsenic poisoning is the great variety of
sympt-oms that can be produced.
Dangerous; when heated to decomposition,
or when metallic arsenic contacts acids or
acid fumes, or when water solutions of
arsenicals are in contact with active metals
such as Fe, Al, or Zn, highly toxic fumes of
arsenic are emitted.
Purification Methods
It crystallises from acetone and sublimes below 100o. It is very slowly hydrolysed by H2O (much more slowly than the chloride). POISONOUS. [Schenk in Handbook of Preparative Inorganic Chemistry (Ed. Brauer) Academic Press Vol I p 597-598 1963.]
Check Digit Verification of cas no
The CAS Registry Mumber 7784-45-4 includes 7 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 4 digits, 7,7,8 and 4 respectively; the second part has 2 digits, 4 and 5 respectively.
Calculate Digit Verification of CAS Registry Number 7784-45:
(6*7)+(5*7)+(4*8)+(3*4)+(2*4)+(1*5)=134
134 % 10 = 4
So 7784-45-4 is a valid CAS Registry Number.
InChI:InChI=1/AsH3.3HI/h1H3;3*1H/q+3;;;/p-3
7784-45-4Relevant articles and documents
Hewitt, J. T.,Winmill, T. F.
, p. 962 - 964 (1907)
Synthesis of a Homologous Series of Trialkyl Arsines (C3-C12) and Applications of Arsenic Triiodide as a Synthetic Precursor
Ligiéro, Carolina B.P.,Francisco, Marcos A.S.,Gama, Michelle S.,Carbonezi, Carlos A.,Leocadio, Isabela C.L.,de Souza, Wladmir F.,Esteves, Pierre M.
, p. 912 - 916 (2021/03/17)
This work presents some modifications in the post-synthetic processing for a classical arsenic reagent: AsI3. In comparison with the widely used analog, the trichloride, arsenic triiodide presents several advantages such as low toxicity, air stability, and low volatility. It was used as a synthetic precursor in the preparation of a variety of arsenic(III) derivatives like arsines, arsenites, and thioarsenites. Besides that, AsI3 was submitted to a diversity-oriented Grignard reaction in the preparation of a homologous series of trialkyl arsines ranging from AsC3H9 to AsC12H27. The series was analyzed by comprehensive two-dimensional gas chromatography coupled with time-of-flight mass spectrometry to provide a trialkyl arsines library that can be used for the direct analysis of natural samples.
Preparation of stable AsBr4+ and I2As-PI 3+ salts. Why didn't we succeed to prepare AsI 4+ and As2X5+? A combined experimental and theoretical study
Gonsior, Marcin,Krossing, Ingo
, p. 1203 - 1213 (2007/10/03)
In analogy to our successful PX2+ insertion reactions, an AsX2+ insertion route was explored to obtain new arsenic halogen cations. Two new salts were prepared: AsBr4+[Al(OR)4]-, starting from AsBr3, Br2 and Ag[Al(OR)4], and I 2As-PI3+[Al(OR)]4 from AsI 3, PI3 and Ag[Al(OR)4] (R = C(CF 3)3). The first cation is formally a product of an AsBr2+ insertion into the Br2 molecule and the latter clearly a PI2+ insertion into the As-I bond of the AsI3 molecule. Both compounds were characterized by IR and NMR spectroscopy, the first also by its X-ray structure. Reactions of Ag[Al(OR)4] with AsI3 do not lead to ionization and Agi formation but rather lead to a marginally stable Ag(AsI3)2+[Al(OR)]4 salt. Despite many attempts we failed to prepare other PX-cation analogues such as AsI 4+, As2X5+ and P 4AsX2+ (X = Br, I). To explain these negative results the thermodynamics of the formation of EX2+, EX4+ and E2X5+ (E = As, P; X = Br, I) was carefully analyzed with MP2/TZVPP calculations and inclusion of entropy and solvation effects. We show that As2Br5 + is in very rapid equilibrium with AsBr2+ and AsBr3 (ΔG°(CH2Cl2) = +30 kJ mol -1). The extremely reactive AsBr2+ cation available in the equilibrium accounts for the observed decomposition of the [Al(OR)4]- anion. By contrast, the stability of AsI 3 against Ag[Al(OR)4] appears to be kinetic and, if prepared by a suitable route, As2I5+ would be expected to have a stability intermediate between the known P2I 5+ and P2Br5+. The Royal Society of Chemistry 2005.
