User:Petergans

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Lecturer etc. in inorganic chemistry Leeds University 1964-2003

Strong interest in the application of numerical methods to experimental data (e.g. Numerical smoothing and differentiation, Molecular vibration)

Since 1972, together with Italian colleagues developed general purpose computer programs to obtain stability constants from experimental data - ongoing project. Major contributor to articles relating to equilibria in solution, including, chemical equilibrium, equilibrium constant, determination of equilibrium constants, acid dissociation constant and stability constants of complexes: personal web-site.

Wiki Howlers

Star howlers

• Solubility equilibrium (version 3 July 2010) many solids will become more soluble with increasing temperature, regardless of Le Chatelier's Principle
• pH (as of 26 May 2012) the units of pH are log(L/mol), although this is seldom indicated explicitly

Howlers corrected

• Metal ions in aqueous solution version 24 Sept.2013. Raman spectroscopy is particularly useful because the excitation wavelength for the Raman spectra could be choosen in the region of water's transparancy. Nonsense! It's nothing to do with excitation wavenength. Reverted
• Savitzky-Golay smoothing filter, version 09:57, 30 May 2013. Omitted value of the data interval in the expressions for derivatives.
• Radioactive tracer Phosphorus-32 is frequently used to label amino acids. Revised
• Radioactive tracer Tritium and carbon-14-labeled water and glucose are commonly used.. Revised
• Fractional crystallization (chemistry) [In] fractional crystallization [of] two or more substances they will crystallize out of solution (precipitate) at different rates. It is not a matter of rates, but of different solubility products which determine the equilubrium state.
• polyphosphate: .. are anionic phosphate polymers linked between hydroxyl groups and hydrogen atoms. Article extensively revised
• EDTA is an amino acid. Replaced by polyamino carboxylate.
• Lutetium is a d-block element In transition metal, version 2 Aug 2009
• Caption to image "basic zinc acetate.png" labelled zinc acetate. Featured article zinc!!!
• Niobium is in many ways similar to its predecessors in group 4. Featured article niobium!!! Changed to group 5.
• metaphosphate A metaphosphate is a salt or an ester of metaphosphoric acid, HPO3
• reduction potential The half cell standard potential $E_{0}$ is given by $E_{0} (\textrm{volts}) = -\frac{\Delta G}{nF}$ where Δ G is the Gibbs free energy change. Changed to standard free energy change.
• Solubility equilibrium (version 3 July 2010) many solids will become more soluble with increasing temperature, regardless of Le Chatelier's Principle
• Crystal field excitation dd-transitions on a copper atom that is surrounded by a hexagon of oxygen atoms. Changed in Revision as of 19:38, 17 May 2010 to an octahedra. Finally changed to an octahedron.
• Recrystallization (chemistry) Since "Compound A" is in excess this will usually result in these crystals forming first see fractional crystallization, above
• Molecular vibration (version 19 December 2010) The three atomic molecule have three modes of vibration irrespective of whether these are linear or nonlinear. Confuses normal modes of vibration with vibration frequencies.
• Hydroxide (version 5 December 2010) When hydroxide ion is mixed with hydrogen gas, water forms. Article re-written.
• Zwitterion (Version 27 Dec. 2010) Most amino acids at physiological pH are zwitterionic. Confusion between biological pH and isoelectric point.
• uranyl: (Version 23 Jan 2011) Examples of uranyl compounds include uranium trioxide Whole article revised.
• Technetium-99m(Earlier version):The molybdenum-99 is in the form of sodium molybdate in ion resins. When the Mo-99 decays to Tc-99m this does not form a similar compound Corrected by another editor.
• Borate the fictitious ions [ .. H2BO
3
, HBO2−
3
and BO3−
3
]
are easier to use for pKa values and other calculations. Article revised.
• Uranate Uranate is the chemical term for oxide anions of the element uranium. Examples of uranates include UO22-, UO32−, and UO42− Article re-written.
• pH "The meaning of the "p" in "pH" is unknown". No it isn't. It means decimal cologarithm
• pH "where aH+ is the activity of hydrogen ions in units of mol/L (molar concentration)" Logarithms can only be taken of numbers, so the idea of taking a logaritm of a concentration is nonsense. In fact activity is dimensionless.
• Electromagnetic absorption by water Rotational transitions don't affect significantly the absorption spectrum of water. Complete omission of vibration-rotation effects. Article re-wrtten
• Buffer solution (Revision as of 08:43, 6 May 2013) most of the added hydroxide ion is consumed in the reaction OH- + HA → H2O + A- ... which results in a decrease in pH. Corrected by user:Edgar181
• Borax (as of 1 Oct 2013)... is a salt of boric acid. changed to with an empirical formula Na2B4O7nH2O·
• Sodium hydroxide (As of 1 Oct 2013) Sodium hydroxide slowly reacts with glass to form sodium silicate. Glass dissolves, forming soluble silicates.
• Ascorbic acid (As of 1 Oct 2013) [..] behaves as a vinylogous carboxylic acid. Re-written in terms of electron delocalization stabilizing the ascorbate anion.
• Fluorinated ethylene propylene ... initiated with persulfate, which homolyzes to generate sulfate radials. A brilliant typo!

Not yet corrected

• Carbonate#Biological significance H+ is generated from carbonic acid (H2CO3) which has ultimately come from inhaled CO2(g)
• Nitric oxide In the case of a bent M-N-O ... One can view such complexes as derived from NO+ Confusion between NO+ and NO-!
• Bond dissociation energy :H2 → 2 H· ΔG = 102 kcal/mol Temperature and pressure not stated. ΔG?
• Vanadate Can you believe this structure!

Failed initiatives

This list highlights articles which could not be improved due to intransigence of other editors.

• Convolution The definition of discrete convolution is flawed, as discussed on the talk page.
• Chemical equilibrium Other editors insist on the primacy of the kinetic criterion over the thermodynamic criterion. The thermodynamic approach is used in Equilibrium chemistry.

Stars

 The Original Barnstar Thank you for your extensive contribution to Wikipedia articles on chemistry. Stan J. Klimas (talk) 14:46, 7 December 2008 (UTC)
 The Chemistry Star It is good to have you around! Qualitity articles pave your way. Stone (talk) 23:11, 11 March 2009 (UTC)
 The Resilient Barnstar Hi Petergans! I'm glad you learnt to add the references. Unfortunately, it lacks third-party sources. Otherwise, its notability will be challenged. Thanks for your attention. All the best, Kayau (Talk to me! See what I've done! Sign my guestbook!) 05:04, 4 July 2009 (UTC)
 The Original Barnstar For your work on expanding and clarifying the Radioactive tracer article. Thank you! Dac04 (talk) 15:49, 17 May 2012 (UTC)
 The Editor's Barnstar Just saw your oxyhalide page. Great stuff. Kudos. TCO (talk) 17:28, 14 July 2012 (UTC)