| 词条 | Calcium arsenate |
| 释义 |
| Verifiedfields = changed | Watchedfields = changed | verifiedrevid = 440601674 | Name = Calcium arsenate | ImageFile = Calciumarsenaat.png | ImageSize = | ImageName = Calcium arsenate | ImageFile2 = Arsenian Wapnia.jpg | ImageSize2 = | ImageName2 = Calcium arsenate | OtherNames = Calcium orthoarsenate Cucumber dust Tricalcium arsenate Tricalcium ortho-arsenate |Section1={{Chembox Identifiers | CASNo = 7778-44-1 | CASNo_Ref = {{cascite|correct|??}}= | PubChem = 24501 | RTECS = CG0830000 | KEGG_Ref = {{keggcite|correct|kegg}} | KEGG = C18647 | EINECS = 233-287-8 | ChemSpiderID_Ref = {{chemspidercite|changed|chemspider}} | ChemSpiderID = 22909 | SMILES = [O-][As](=O)([O-])[O-].[O-][As](=O)([O-])[O-].[Ca+2].[Ca+2].[Ca+2] | InChI = 1/2AsH3O4.3Ca/c2*2-1(3,4)5;;;/h2*(H3,2,3,4,5);;;/q;;3*+2/p-6 | InChIKey = RMBBSOLAGVEUSI-CYFPFDDLAC | StdInChI_Ref = {{stdinchicite|changed|chemspider}} | StdInChI = 1S/2AsH3O4.3Ca/c2*2-1(3,4)5;;;/h2*(H3,2,3,4,5);;;/q;;3*+2/p-6 | StdInChIKey_Ref = {{stdinchicite|changed|chemspider}} | StdInChIKey = RMBBSOLAGVEUSI-UHFFFAOYSA-H |Section2={{Chembox Properties | Formula = Ca3(AsO4)2 | MolarMass = 398.072 g/mol | Appearance = white powder | Odor = odorless | Density = 3.62 g/cm3, solid | Solubility = 0.013 g/100 mL (25 °C)[1] | Solvent1 = Organic solvents | Solubility1 = insoluble | Solvent2 = acids | Solubility2 = soluble | MeltingPtC = 1455 | MeltingPt_notes = (decomposes) | BoilingPt = |Section3={{Chembox Hazards | NFPA-H = 4 | NFPA-R = 0 | NFPA-F = 0 | NFPA-S = | LD50 = 20 mg/kg (rat, oral) 812 mg/kg (rat, oral) 794 mg/kg (mouse, oral) 50 mg/kg (rabbit, oral) 38 mg/kg (dog, oral)[2] | PEL = TWA 0.010 mg/m3[3] | IDLH = 5 mg/m3 (as As)[3] | REL = Ca C 0.002 mg/m3 [15-minute][3] | MainHazards = carcinogen[3] | FlashPt = noncombustible | FlashPt_notes = [3] }}Calcium arsenate is the inorganic compound with the formula Ca3(AsO4)2. A colourless solid, it was originally used as a pesticide and as a germicide. It is highly soluble in water, as compared with lead arsenate, which makes it more toxic. The minerals Rauenthalite Ca3(AsO4)2·10H2O and Phaunouxite Ca3(AsO4)2·11H2O are hydrates of calcium arsenate.[4] PreparationCalcium arsenate is commonly prepared from disodium hydrogen arsenate and calcium chloride: 2 Na2H[AsO4] + 3 CaCl2 → 4 NaCl + Ca3[AsO4]2 + 2 HCl In the 1920s, it was made in large vats by mixing calcium oxide and arsenic oxide.[5] In the United States, 1360 metric tons were produced in 1919, 4540 in 1920, and 7270 in 1922.[1] The composition of commercially available calcium arsenate varies from manufacturer to manufacturer. A typical composition is 80-85% of Ca3(AsO4)2 a basic arsenate probably with a composition of 4CaO.As2O5 together with calcium hydroxide and calcium carbonate.[4] Use as a herbicideIt was once a common herbicide and insecticide. 38,000,000 kilograms were reported to be produced in 1942 alone, mainly for protection of cotton crops. Its high toxicity led the development of DDT.[6] RegulationCalcium arsenate use is now banned in the UK, and its use is strictly regulated in the United States. It is currently the active ingredient in TURF-Cal manufactured by Mallinckrodt, it is one of the few herbicides – used mainly for the control of Poa annua and crabgrass- that hinders earthworm activity. Its label states that it will "reduce and inhibit earthworm activity and survival" and is only recommended against serious earthworm infestations in places such as golf course greens.[7] Toxicity and regulationCalcium arsenate is highly toxic, having both carcinogenic and systemic health effects.[8] The Occupational Safety and Health Administration has set a permissible exposure limit at 0.01 mg/m3 over an eight-hour time-weighted average, while the National Institute for Occupational Safety and Health recommends a limit five times less (0.002 mg/m3).[9] It is classified as an extremely hazardous substance in the United States as defined in Section 302 of the U.S. Emergency Planning and Community Right-to-Know Act (42 U.S.C. 11002), and is subject to strict reporting requirements by facilities which produce, store, or use it in significant quantities.[10] References1. ^1 Tartar, H.V.; Wood, L; Hiner, E; A Basic Arsenate of Calcium. J. Am. Chem. Soc. 1924, vol. 46, 809-813. {{Calcium compounds}}{{Insecticides}}{{DEFAULTSORT:Calcium Arsenate}}2. ^{{IDLH|7778441|Calcium arsenate (as As)}} 3. ^1 2 3 4 {{PGCH|0089}} 4. ^1 {{cite book|last=Ropp|first=Richard|title=Encyclopedia of the Alkaline Earth Compounds|year=2012|publisher=Newnes|isbn=0444595538|page=76}} 5. ^Smith, C.M.; Murray, C.W.; The Composition of Commercial Calcium Arsenate. Journal of Industrial and Engineering Chemistry; 1931, 23 6. ^Robert L. Metcalf "Insect Control" in Ullmann’s Encyclopedia of Industrial Chemistry Wiley-VCH, Weinheim, 2002. {{DOI|10.1002/14356007.a14_263}} 7. ^{{cite web | title=Turf insect pest control guide: Urban Phytonarian Series | url=http://learningstore.uwex.edu/assets/pdfs/A2934.pdf | first=C.F. | last=Koval | publisher=College of Agricultural and Life Sciences - University of Wisconsin-Madison | accessdate=9 November 2018 }} 8. ^Tchounwou, P.B.; Patlolla, A.K.; Centeno, J.A.; Carcinogenic and Systematic Health Effects Associated with Arsenic – A Critical Review. Toxicologic Pathology; 2003, 31, 575-588 9. ^{{cite web| title = Calcium Arsenate| work = NIOSH Pocket Guide to Chemical Hazards| publisher = Centers for Disease Control and Prevention| date = 4 April 2011| url = https://www.cdc.gov/niosh/npg/npgd0089.html| accessdate = 18 November 2013}} 10. ^{{Cite journal | publisher = Government Printing Office | title = 40 C.F.R.: Appendix A to Part 355—The List of Extremely Hazardous Substances and Their Threshold Planning Quantities | url = http://edocket.access.gpo.gov/cfr_2008/julqtr/pdf/40cfr355AppA.pdf | edition = 1 July 2008 | accessdate = 29 October 2011 | postscript=.}} 5 : Arsenates|Calcium compounds|Insecticides|Mutagens|Carcinogens |
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