The Dipole Moments Of H3cf And H3sif: A Cndo/2 Localized Molecular Orbital Study

[No abstract available]15CL13L14Ebsworth, (1968) Organometallic Compounds of the Group IV Elements, 1, p. 81. , A.G. MacDiarmid, Marcel Dekker, New YorkBellama, Morrison, (1975) Inorg. Nucl. Chem. Letters, 11, p. 127Kuznesof, Pessine, Bruns, Shriver, (1975) Inorg. Chim. Acta, 14, p. 000Trindle, Sinanoglu, Semiempirical Method for the Determination of Localized Orbitals in Molecules (1968) The Journal of Chemical Physics, 49, p. 65Edmiston, Reudenberg, (1965) J. Chem. Phys., 43, p. S97Edmiston, Reudenberg, (1963) Rev. Mod. Phys., 35, p. 457Pople, Beveridge, (1970) Approximate Molecular Orbital Theory, , McGraw-Hill, New YorkR. E. Bruns, Quantum Chemistry Program Exchange, Indiana University, Bloomington, Indiana, Program no. 240Santry, (1968) J. Am. Chem. Soc., 90, p. 3309P. M. Kuznesof, QCPE Program No. 267Interatomic Distances, Chemical Society Special Publication no. 11, L. E. Sutton, ed., London (1958)Kewley, McKinney, Robiette, (1970) J. Molec. Struct., 34, p. 390Santry, Segal, (1967) J. Chem. Phys., 47, p. 158Krishner, Morrison, Watson, Microwave Spectrum of Fluorogermane, GeH3F and GeD3F (1972) The Journal of Chemical Physics, 57, p. 135

Dipole Moment Derivatives And Vibrational Intensities Of Bcl3

The CNDO approximate molecular wavefunctions for BCl3 have been applied to the calculation of the derivatives of the dipole moment with respect to the symmetry coordinates. New experimental derivatives calculated from previously published intensity data are presented. The set of experimental derivatives with respect to internal coordinates definitely preferred by these calculations is that with all signs negative. Inclusion of the d Orbitals of chlorine in the atomic orbital basis set markedly influences the magnitudes of the derivatives as well as improves the agreement with the experimental in-plane and out-of-plane bending derivatives. The pd polarization terms appear to play an important role. Our results for BCl3 are compared with those previously obtained for BF3.4362436

Donor-acceptor Interactions Of Substituted Benzenes With Molecular Chlorine And Carbon Disulfide

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)CNDO molecular orbital calculations have been performed to analyze donor-acceptor interactions between molecular chlorine and benzene, toluene, mesitylene and hexamethylbenzene and the, as yet, unreported chlorine-hexafluorobenzene and carbon disulfide-benzene pairs. The stabilization energy and the dipole moment and its derivative (∂p/∂RCICI) calculated for the benzene-chlorine complex are in good agreement with the estimated experimental values. The trends in the experimental stabilization energies and the Cl-Cl vibrational frequencies with increasing methyl substitution appear to be well reproduced by the calculations. The charge transferred from the benzene donor is polarized toward the outer chlorine atom or sulfur atom. For hexafluorobenzene-chlorine the direction of electronic charge polarization is reversed from that of the benzene and methylbenzene complexes. The calculated results are discussed within the framework of Muliiken's simplified resonance theory for complexes. © 1975.292211223CAPES; Coordenação de Aperfeiçoamento de Pessoal de Nível SuperiorCoordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Mulliken, Person, (1969) Molecular Complexes, , John Wiley and Sons, New YorkHanna, (1968) J. Amer. Chem. Soc., 90, p. 285Hanna, Wlliams, (1968) J. Amer. Chem. Soc., 90, p. 5358Lippert, Hanna, Trotter, (1969) J. Amer. Chem. Soc., 91, p. 4035Person, (1973) Spectroscopy and Structure of Molecular Complexes, , J. Yarwood, Plenum Press, London, Chap. IClementi, (1967) J. Chem. Phys., 46, p. 3851Clementi, (1967) J. Chem. Phys., 47, p. 2323Clementi, Gayles, (1967) J. Chem. Phys., 47, p. 3837Carreira, Person, (1972) J. Amer. Chem. Soc., 94, p. 1485Pople, Beveridge, (1970) Approximate Molecular Orbital Theory, , McGraw Hill, New YorkChestnut, Wormer, The TCNE-benzene complex: A CNDO approach (1971) Theoretica Chimica Acta, 20, p. 250Nelander, (1972) Theor. Chim. Acta, 25, p. 382Tamres, (1964) J. Phys. Chem., 68, p. 2621a P.R. Dobosh, Quantum Chemistry Program Exchange, Department of Chemistry,Indiana University, Bloomington, Indiana, program No. 141b P.M. Kuznesof, QCPE program No. 94Pople, Segal, (1966) J. Chem. Phys., 44, p. 3289Santry, (1968) J. Amer. Chem. Soc., 90, p. 3309Mulliken, (1955) J. Chem. Phys., 23, p. 1833Mulliken, (1955) J. Chem. Phys., 23, p. 1841Mulliken, (1955) J. Chem. Phys., 23, p. 2338Mulliken, (1955) J. Chem. Phys., 23, p. 2343a P.R. Dobosh, Quantum Chemistry Program Exchange, Department of Chemistry,Indiana University, Bloomington, Indiana, program No. 141Ralston, (1965) A First Course in Numerical Analysis, p. 46. , McGraw-Hill, New YorkHassel, Stromme, Crystal Structure of the Addition Compound Benzene-Chlorine (1:1). (1959) Acta Chemica Scandinavica, 13, p. 1781Mulliken, (1952) J. Amer. Chem. Soc., 74, p. 811Brundle, Robin, Kueblen, (1972) J. Amer. Chem. Soc., 94, p. 1466Marschner, Goetz, (1973) Tetrahedron, 29, p. 3105Andrews, Keefer, (1952) J. Amer. Chem. Soc., 74, p. 4500Bhowmik, (1971) Spectrochim. Acta, Part A, 27, p. 321. , the effect of solvent on the formation constants and spectral properties of benzene-I2 and benzene and mesitylene—TCNE complexes has recently been examined byBhowmik, Srimani, (1973) Spectrochim. Acta, Part A, 29, p. 935Ferguson, Matsen, (1960) J. Amer. Chem. Soc., 82, p. 3268Kortüm, Walz, (1953) Z. Elektrochem., 7 R, p. 73. , report a much higher value of 1.80 D. Since the CNDO theory has overestimated the amount of charge transfer it seems more realistic to compare our calculated value of 1.12 D with the value of 0.72 DFleming, Hanna, Nuclear quadrupole resonance investigation of iodine monochloride complexed with pyridines (1971) Journal of the American Chemical Society, 93, p. 5030Bowmaker, Hacobian, Nuclear quadrupole resonance of charge-transfer complexes. II. The aminehalogen complexes (1969) Australian Journal of Chemistry, 22, p. 2047Klaboe, (1967) J. Amer. Chem. Soc., 89, p. 3667Rosen, Shen, Stenman, Raman study of iodine complexes in solutions (1971) Molecular Physics, 22, p. 33b P.M. Kuznesof, QCPE program No. 94Person, Erickson, Buckles, (1960) J. Amer. Chem. Soc., 82, p. 29Segal, Klein, (1967) J. Chem. Phys., 47, p. 4236Fredin, Nelander, (1974) J. Amer. Chem. Soc., 96, p. 1672Fredin, Nelander, On the structure of benzene halogen complexes (1974) Molecular Physics, 27, p. 88

The Carbonyl Vibration In α-group Iv Metal Ketones

Overend and Scherer's perturbation theory treatment (Spectrochim. Acta, 16 (1960) 773) of ν(CO) is applied to R3MCOR′ and R3MCOMR3 (M = C, Si, Ge, Sn). Corrected group frequencies, ν*(CO), which exclude effects extraneous to the CO bond (e.g. molecular geometry and potential energy contributions from internal coordinates other than the CO bond) and which reflect the true strength of the CO bond are calculated. Results are interpreted in terms of Si(dπ)←CO(π) interactions out-weighing silicon's +I inductive effect in lowering ν(CO). Surprisingly, α-metal-CO electronic interactions appear to be of similar magnitude for C, Ge, and Sn. Our conclusions do not contradict the interpretation of the basicity order for the α-metal ketones in terms of relative inductive effects of M since the basicities depend on the availability of the non-bonding σ electrons of oxygen. In fact, the greater +I of silicon may be expected to promote more effective (d-p)π back-donation. A comment concerning the CO vibration in β-silyl ketones is given. © 1973.56C131140Brook, (1957) J. Amer. Chem. Soc., 79, p. 4373Bock, Alt, Seidl, (1969) J. Amer. Chem. Soc., 91, p. 355. , and references thereinBrook, (1968) Advan. Organometal. Chem., 7, p. 95Brook, Quigley, Peddle, Schwartz, Warner, (1960) J. Amer. Chem. Soc., 82, p. 5102Brook, Pierce, (1964) Canadian Journal of Chemistry, 42, p. 298Peddle, (1966) J. Organometal. Chem., 5, p. 486Peddle, (1968) J. Organometal. Chem., 14, p. 115Peddle, (1968) J. Organometal. Chem., 14, p. 139Yates, Agolini, (1966) Canadian Journal of Chemistry, 44, p. 2229Harrison, Trotter, (1968) Journal of the Chemical Society A: Inorganic, Physical, Theoretical, p. 258Chieh, Trotter, (1969) Journal of the Chemical Society A: Inorganic, Physical, Theoretical, p. 1778Kuznesof, Pessini, Bruns, (1972) J. Amer. Chem. Soc., 94, p. 9087Overend, Scherer, (1960) Spectrochim. Acta, 16, p. 773Halford, (1956) J. Chem. Phys., 24, p. 830Miyazawa, (1953) Nippon kagaku zassi, 74, p. 915Overend, Scherer, (1960) Spectrochim. Acta, 16, p. 773Hansen, Dennison, (1952) J. Chem. Phys., 20, p. 313Tannon, Weiss, Nixon, (1970) Spectrochimica Acta Part A: Molecular Spectroscopy, 26 A, p. 221Kimmel, Dillard, (1968) Spectrochim. Acta, 24 A, p. 909Shimanouchi, (1963) Pure and Applied Chemistry, 7, p. 131Adelfang, Hess, Cromwell, (1961) J. Org. Chem., 26, p. 1402Bellamy, Williams, (1957) Journal of the Chemical Society (Resumed), p. 4294Corey, Seebach, Freedman, (1967) J. Amer. Chem. Soc., 89, p. 434Bartlett, Stiles, (1955) J. Amer. Chem. Soc., 77, p. 2806Brook, Peddle, (1966) J. Organometal. Chem., 5, p. 106Brook, Jones, Peddle, (1968) Canadian Journal of Chemistry, 46, p. 2119Bock, Seidl, (1968) Journal of the Chemical Society B: Physical Organic, p. 1158Steward, Dziedzic, Johnson, (1971) J. Org. Chem., 36, p. 3475Brook, (1968) Advan. Organometal. Chem., 7, p. 95Ramsey, (1969) Electronic Transitions in Organometalloids, p. 101. , Academic Press, New YorkPauling, (1960) The Nature of the Chemical Bond, p. 257ff. , 3rd ed., Cornell University Press, Ithaca, N.YBellamy, (1968) Advances in Infrared Group Frequencies, p. 133. , Methuen, LondonShaw, III, Allred, (1970) Organometal. Chem. Rev. A, 5, p. 95Attridge, (1970) Organometal. Chem. Rev. A, 5, p. 323Nakamoto, (1970) Infrared Spectra of Inorganic and Coordination Compounds, p. 9. , 2nd ed., Wiley-Interscience, New Yor

Acidities And Spectral Properties Of α-silyl And α-germyl Carboxylic Acids And Their Carboxylates

The order of acidity observed for R3MCO2H (R = CH3 and/or C6H5, M = C, Si, Ge; R = H, M = C, Ge) is Si ≥ Ge > C. We find this order is best explained in terms of the larger sizes and polarizabilities of Si and Ge relative to C which would facilitate stabilization of the negative charge in the conjugate base. CNDO/2 results on the model systems H3CCO2H, H3SiCO2H, and their anions are presented (with and without inclusion of d orbitals for Si) which predict the correct order of acidity and indicate pπ → dπ interaction is of little importance, contrary to previous suggestions. The importance of Si-O (1,3) dπ-pπ interactions is also considered. For a consistent thermodynamic explanation the relative electron affinities of CH3 · and SiH3 · (Si > C) appear to be the key factors. The electronic spectra of the title compounds indicate a symmetry (C2v) forbidden n → π* transition as the lowest energy transition. CNDO/2 predicts an allowed σ → π* which cannot be ruled out at present as incorrect, dπ-π* interactions (M = Si) do appear important in determining electronic properties for which there are significant excited-state contributions. Differences in CO stretching frequencies are explained qualitatively in terms of relative Si and C inductive effects. However, comparison of the ir (v(CO)) characteristics of the acids with those of the α-group-IV metal ketones and dihalocarbonyls (for which force constant and normal coordinate data are available) suggest kinetic effects (mass and geometric differences) and potential energy terms not involving the CO bond are more important than electronic effects for determining v(CO).94269087909

Molecular Orbital Studies Of The Dipole Moments Of Methyl Substituted Amines, Phosphines, And Their Borane Adducts

The magnitudes and trends of the dipole moments of MexH3-xE and MexH3-xEBH3 (E = N, P; x = 0→3; Me = CH3) were investigated via CNDO-MO methods. Moments evaluated by the CNDO/2D approach reproduced the experimental data better than the strict CNDO/2 formalism. Transformation of the canonical CNDO/2 MO's to localized MO's (LMO's) permitted a partitioning of the total moments into bond moments, bond polarization moments, and lone pair moments. Values of the lone pair moments of the phosphines are calculated to be greater than those of the amines. Within the framework of the CNDO/2D approximation, coordination of BH3 to H3N involves a charge migration primarily between the N-bound and B-bound hydrogens (0.33e) while coordination to H3P is primarily P → B (0.27e). The covalent character of the BN and BP bonding LMO's is 46 and 61%, respectively. The CNDO molecular orbital results are in general agreement with Weaver and Parry's model for dipole moments and base strengths of amines and phosphines. © 1975.14C271280Presented at the XXV Annual Meeting of the Sociedade Brasileira para o Progresso da Ciencia. Abstract no. 27-C1, Ciěncia Cult., 25, S91 (1973). Abstracted, in part, from the M.S. thesis of F.B.T.P. b, Campinas. c) EvanstonWeaver, Parry, (1966) Inorg. Chem., 5, p. 703Kodama, Weaver, LaRochelle, Parry, Dipole Moment Studies II. The Dipole Moments of the Ethylphosphines (1666) Inorganic Chemistry, 5, p. 710Weaver, Parry, Dipole Moment Studies. III. The Dipole Moments of the Methylamine Boranes (1966) Inorganic Chemistry, 5, p. 713Weaver, Parry, Dipole Moment Studies. IV. Trends in Dipole Moments (1966) Inorganic Chemistry, 5, p. 718Morse, Parry, Dipole Moment Studies. V. The Dipole Moments of the Methylphosphine Boranes (1972) The Journal of Chemical Physics, 57, p. 5365Morse, Parry, (1972) J. Chem. Phys., 57, p. 5367Rudolph, Parry, (1967) J. Am. Chem. Soc, 89, p. 1621Foester, Cohn, (1972) Inorg. Chem., 11, p. 2590Rudolph, Schultz, (1971) J. Am. Chem. Soc., 93, p. 6821Cowley, Damasco, (1971) J. Am. Chem. Soc., 93, p. 6815Lee, Cohn, Schwendeman, (1972) Inorg. Chem., 11, p. 1917Pople, Beveridge, (1970) Approximate Molecular Orbital Theory, , McGraw-Hill, New YorkShillady, Billingsley, II, Bloor, Quantum mechanical calculations on barriers to internal rotation (1968) Theoretica Chimica Acta, 11, p. 344Shillady, (1970) Ph.D. Thesis, , University of VirginiaGiessner-Prettre, Pullman, (1968) Theoret. Chim. Acta., 11, p. 159Trindle, Sinanoglu, Semiempirical Method for the Determination of Localized Orbitals in Molecules (1968) The Journal of Chemical Physics, 49, p. 65Edmiston, Reudenherg, (1965) J. Chem. Phys., 43, p. S97Edmiston, Reudenberg, (1963) Rev. Mod. Phys., 35, p. 457England, Salmon, Reudenberg, (1971) Topics in Current Chemistry, 23, p. 31. , Springer-Verlag, BerlinWon Nicssen, Density localization of atomic and molecular orbitals (1973) Theoretica Chimica Acta, 29, p. 29. , and references thereinLabarre, Leibovici, Structure electronique des complexes acide-base de Lewis. I. Structure electronique et conformation mol�culaire des mol�cules F3P�BH3 et F2HP�BH3 (1972) International Journal of Quantum Chemistry, 6, p. 625. , CNDO, F3PBH3 and F2HPBH3Sabin, (1973) Chem. Phys. Letts., 20, p. 212. , ab initio, H3PBH3Demuynck, Veillard, (1970) J. Chem. Soc. (D), p. 873. , ab initio, F3PBH3Hillier, Marriott, Saunders, Ware, Lloyd, Lynaugh, (1970) J. Chem. Soc. (D), p. 1586. , ab initio F3PBH3Hillier, Saunders, An ab initio study of the bonding in phosphine borane, trifluorophosphine broane and trifluorophosphine oxide (1971) Journal of the Chemical Society A: Inorganic, Physical, Theoretical, p. 664. , ab initio F3PBH3 and H3PBH3Palke, (1972) J. Chem. Phys., 56, p. 5308. , ab initio H3PBH3Kroll, Shillady, (1973) J. Am. Chem. Soc., 95, p. 1422. , ab initio, aziridineboraneFujimote, Kato, Yamabe, Fukui, Molecular orbital calculations of the electronic structure of borazane (1974) The Journal of Chemical Physics, 60, p. 572. , ab initio H3NBH3Armstrong, Perkins, Calculation of the electronic structures and the gas-phase heats of formation of BH3,NH3 and BH3,CO (1969) Journal of the Chemical Society A: Inorganic, Physical, Theoretical, p. 1044. , ab initio, H3NBH3Aslangul, Veillard, Daudel, Gallais, (1971) Theoret. Chim. Acta., 23, p. 211. , ab initio H3NBH3Tinland, An ab initio SCF-LCAO-MO study of the electronic structure of borazane, BH3NH3 (1969) Journal of Molecular Structure, 3, p. 244. , ab initioPeyerimhoff, Buenker, Further Study of Umbrella vs Bridged Geometries: SCF–MO and CI Calculations for C2H6++ and Ammonia Borane (1968) The Journal of Chemical Physics, 49, p. 312. , ab initio, H3NBH3Moireau, Veillard, (1968) Theoret. Chim. Acta., 11, p. 344. , ab initio H3NBH3Veillard, Levy, Daudel, Gallais, (1967) Theoret. Chim. Acta., 8, p. 312. , ab initio, H3NBH3Kuznesof, Shriver, (1968) J. Am. Chem. Soc., 90, p. 1683. , CNDOKuznesof, (1967) Ph.D. Dissertation, , Northwestern University, preliminary study (CNDO) of the dipole moments of the methylamine boranes is presented hereHoffmann, Theoretical Investigations on Boron-Nitrogen Molecules (1964) Adv. Chem. Ser., 42, p. 78Hoffmann, (1964) J. Chem. Phys., 40, p. 2474. , Extended Hückel, H3NBH3Guest, Hillier, Saunders, (1972) J.C.S. Faraday II, 68, p. 867Rothenberg, (1971) J. Am. Chem. Soc., 93, p. 68Pritchard, Kern, (1969) J. Am. Chem. Soc., 91, p. 1631Newton, Switkes, Lipscomb, (1970) J. Chem. Phys., 53, p. 2645Evans, Huheey, (1970) J. Inorg. and Nucl. Chem., 32, p. 777. , and references thereinJolly, Perry, (1973) J. Am. Chem. Soc., 95, p. 5442University of California Lawrence Radiation Laboratory Report LBL-2565Jolly, Perry, (1974) Inorg. Chem., 13, p. 2686R.E. Bruns, Quantum Chemistry Program Exchange, Department of Chemistry, Indiana University, Bloomington Indiana program no 240Santry, (1968) J. Am. Chem. Soc., 90, p. 3309P.M. Kuznesof, submitted to QCPE. A listing is available on request. The localization procedure follows the ERTS method (refs. 7a, c) and, furthermore, is faster than a similar sub-program LOCAL currently available from QCPE (no. 191). Incorporation of ORLOC into CINDOM or CNINDO (QCPE no. 141) involves the same changes as incorporation of LOCAL into CNINDO. Another significant advantage of ORLOC is that it does not require the introduction of any additional matrices as does LOCAL. ORLOC is also available from the author as an independent program requiring as input only the CMO's and coulomb repulsion integralsP.M. Kuznesof, Quantum Chemistry Program Exchange, Departrnent of Chemistry, Indiana University, Bloomington, Indiana, program no. 94Boyd, (1972) J. Am. Chem. Soc., 94, p. 64Pople, Segal, (1965) J. Chem. Phys., 43, p. S136Odom, Barnes, Hudgens, Durig, (1974) J. Phys. Chem., 78, p. 1503. , A geometry optimized CNDO/2 calculation on Me3NBH3 gives a dipole moment in excellent numerical agreement with the experimental value. Geometry optimization of Me3N, however, yields essentially no improvement. SeeSantry, Segal, (1967) J. Chem. Phys., 47, p. 158Hillier, Saunders, (1970) J. Chem. Soc. (D), p. 316Bryan, Kuczkowski, (1972) Inorg. Chem., 11, p. 553These authors used WP's estimate for the P-=CH3 moment and they settled on the range 3.4- 4.0D for the P-BH3 moment because of an ambiguity arising in their estimate of this moment in CH3PH2BH3. For this molecule they calculated 3.92 and 3.44D depend- ing on which dipole components they selected for their analysisStamper, Trinajastic, Localised orbitals for some simple molecules (1967) Journal of the Chemical Society A: Inorganic, Physical, Theoretical, p. 782. , Values for the nitrogen lone pair moment in NH3 have been previously reported, ranging from 3.4 to 3.8D depending on the starting SCF-CMO's. SeePeters, 764. Localised molecular orbitals in self-consistent field wave functions. Part III. Hybridisations, atomic charges, and dipole moments in non-linear molecules (1963) Journal of the Chemical Society (Resumed), p. 4017Peters, Localised molecular orbitals in self-consistent field wave functions. Part X. The nature of electronegativity (1966) Journal of the Chemical Society A: Inorganic, Physical, Theoretical, p. 656. , Peters has carried out extensive studies regarding the nature and applicability of LMO's. See, and references thereinCoulson, (1961) Valence, p. 218. , 2nd ed., Oxford University Press, LondonSchaefer, III, (1972) The Electronic Structure of Atoms and Molecules, p. 197. , Addison-Wesley, Reading, MassCNDO/2 results obtained for H3PBH3 and Me3PBH3 using their experimental geometries did not significantly differ from the results presented in this workVan Wazer, Callis, Shoolery, Jones, (1956) J. Am. Chem. Soc., 78, p. 5715We define percentage covalent character as where the summation is over the atomic orbitals of atoms R, S, or bothBrauman, Blair, The bicyclo[3.2.2]nonatrienyl anion. The anionic analog of the norbornadienyl cation (1968) Journal of the American Chemical Society, 90, p. 6562Brauman, Riveros, Blair, (1971) J. Am. Chem. Soc., 93, p. 3914McDaniel, Coffman, Strong, (1970) J. Am. Chem. Soc., 92, p. 6697Holtz, Beauchamp, (1969) J. Am. Chem. Soc., 91, p. 5913Beauchamp, Ion Cyclotron Resonance Spectroscopy (1971) Annual Review of Physical Chemistry, 22, p. 527Santry, Segal, (1967) J. Chem. Phys., 47, p. 158. , phosphinesWatanabe, (1957) J. Chem. Phys., 26, p. 542. , amine

Towards internationally acceptable standards for food additives and contaminants based on the use of risk analysis

Internationally acceptable norms need to incorporate sound science and consistent risk management principles in an open and transparent manner, as set out in the Agreement on the Application of Sanitary and Phytosanitary Measures (the SPS Agreement). The process of risk analysis provides a procedure to reach these goals. The interaction between risk assessors and risk managers is considered vital to this procedure. This paper reports the outcome of a meeting of risk assessors and risk managers on specific aspects of risk analysis and its application to international standard setting for food additives and contaminants. Case studies on aflatoxins and aspartame were used to identify the key steps of the interaction process which ensure scientific justification for risk management decisions. A series of recommendations were proposed in order to enhance the scientific transparency in these critical phases of the standard setting procedure. Chemicals/CAS: aflatoxin, 1402-68-2; aspartame, 22839-47-0, 5910-52-