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Drafting pantograph in use Pantograph used for scaling a picture. The red shape is traced and enlarged. Pantograph 3d rendering. A pantograph (from Greek παντ- 'all, every' and γραφ- 'to write', from their original use for copying writing) is a mechanical linkage connected in a manner based on parallelograms so that the movement of one pen, in tracing an image, produces identical ...
Example: P 4. Electron count: 4 × P = 4 × 5 = 20 It is a 5n structure with n = 4, so it is tetrahedral. Example: P 4 S 3. Electron count 4 × P + 3 × S = 4 × 5 + 3 × 6 = 38 It is a 5n + 3 structure with n = 7. Three vertices are inserted into edges. Example: P 4 O 6. Electron count 4 × P + 6 × O = 4 × 5 + 6 × 6 = 56 It is a 5n + 6 ...
A normal experiment may involve 1–10 mL solution with an analyte concentration between 1 and 10 mmol/L. More advanced voltammetric techniques can work with microliter volumes and down to nanomolar concentrations. Chemically modified electrodes are employed for the analysis of organic and inorganic samples.
Ab initio means "from first principles" or "from the beginning", implying that the only inputs into an ab initio calculation are physical constants. [5] Ab initio quantum chemistry methods attempt to solve the electronic Schrödinger equation given the positions of the nuclei and the number of electrons in order to yield useful information such ...
In analytical chemistry, potentiometric titration is a technique similar to direct titration of a redox reaction. It is a useful means of characterizing an acid. No indicator is used; instead the electric potential is measured across the analyte, typically an electrolyte solution.
Electrochemical stripping analysis is a set of analytical chemistry methods based on voltammetry [1] or potentiometry [2] that are used for quantitative determination of ions in solution. [3] Stripping voltammetry (anodic, cathodic and adsorptive) have been employed for analysis of organic molecules as well as metal ions.
Also called direct coulometry, the analyte is oxidized or reduced at the working electrode without intermediate reactions. [6] The working electrode is kept at a constant potential and the current that flows through the circuit is measured. This constant potential is applied long enough to fully reduce or oxidize all of the electroactive ...
Ring opening as a means of ring expansion can also be applied to larger systems to give access to even larger ring syscyclization. The Grob fragmentation can be applied as an example of such an expansion. Like the pinacol type migration the Grob fragmentation relies on an electron donating group to promote the bond migration and encourage the ...