Wikidata:Property proposal/specific rotation

specific rotation[edit]

Originally proposed at Wikidata:Property proposal/Natural science

Done: specific rotation (P6272) (Talk and documentation)

Description	an angle through which plane-polarized light is rotated by an optically active substance or a solution of that substance
Represents	specific rotation (Q2191631)
Data type	Quantity
Domain	chemical substance (Q79529)
Allowed units	degree (Q28390), degree-mililitre per gram-decimetre, etc.
Example 1	dolabriferol B (Q57421096) → -51,9 degree (Q28390) with temperature (P2076) = 20 degree Celsius (Q25267), wavelength (P2808) = 589 nanometre (Q178674), solvent (P2178) = chloroform (Q172275), Pxxx (concentration) = 0,7 gram per 100 mililitres (source: Dolabriferols B and C, non-contiguous polypropionate esters from the tropical sea hare Dolabrifera dolabrifera (Q39107295))
Example 2	dolabriferol C (Q57394391) → -45,2 degree (Q28390) with temperature (P2076) = 20 degree Celsius (Q25267), wavelength (P2808) = 589 nanometre (Q178674), solvent (P2178) = chloroform (Q172275), Pxxx (concentration) = 0,7 gram per 100 mililitres (source: Dolabriferols B and C, non-contiguous polypropionate esters from the tropical sea hare Dolabrifera dolabrifera (Q39107295))
Example 3	(−)-dolabriferol (Q44293768) → -53,0 degree (Q28390) with temperature (P2076) = 20 degree Celsius (Q25267), wavelength (P2808) = 589 nanometre (Q178674), solvent (P2178) = chloroform (Q172275), Pxxx (concentration) = 1,1 gram per 100 mililitres (source: Dolabriferols B and C, non-contiguous polypropionate esters from the tropical sea hare Dolabrifera dolabrifera (Q39107295))
Source	scientific articles, CRC Handbook of Chemistry and Physics (Q904273), chemical databases, etc.

concentration[edit]

Originally proposed at Wikidata:Property proposal/Natural science

Done: concentration (P6274) (Talk and documentation)

Description	qualifier: amount of substance in a mixture (solution) during measurement
Represents	concentration (Q3686031)
Data type	Quantity
Domain	mixture (Q169336) (but in fact used only as a qualifier in items being chemical substance (Q79529))
Allowed units	units of different concentrations: mass concentration (g/kg, g/g, ...), volume concentration (ml/l, ml/dl, ...), molar concentration (mol/l, ...), molal concentration (mol/kg, ...), normal concentration (mval/l, ...), and so on

Motivation[edit]

Specific rotation property is useless without indication of the concentration, so these two proposals shouldn't be discussed separately. The 'concentration' property should be, however, limited to specific properties (like the specific rotation) to avoid putting values of many other properties for mixtures into items describing pure substances (i.e. specific rotation is an important property for chiral chemical compounds that is measured using solutions of a chiral compound in an achiral solvent; but many properties, e.g. density, may be measured for solutions and the values obtained for the solutions are properties of specific solutions, not pure chemical compounds). Wostr (talk) 16:50, 11 December 2018 (UTC)[reply]