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The molecule is planar, Y-shaped and its molecular symmetry belongs to the C 2v point group. [18] The precise molecular geometry of gaseous formaldehyde has been determined by gas electron diffraction [17] [19] and microwave spectroscopy.
The S 2 group is the same as the C i group in the nonaxial groups section. S n groups with an odd value of n are identical to C nh groups of same n and are therefore not considered here (in particular, S 1 is identical to C s). The S 8 table reflects the 2007 discovery of errors in older references. [4] Specifically, (R x, R y) transform not as ...
This group is called the point group of that molecule, because the set of symmetry operations leave at least one point fixed (though for some symmetries an entire axis or an entire plane remains fixed). In other words, a point group is a group that summarises all symmetry operations that all molecules in that category have. [8]
Such species belong to the point group D 3h. Molecules where the three ligands are not identical, such as H 2 CO, deviate from this idealized geometry. Examples of molecules with trigonal planar geometry include boron trifluoride (BF 3), formaldehyde (H 2 CO), phosgene (COCl 2), and sulfur trioxide (SO 3).
There are 230 space groups in three dimensions, given by a number index, and a full name in Hermann–Mauguin notation, and a short name (international short symbol). The long names are given with spaces for readability. The groups each have a point group of the unit cell.
The aldehyde group (or formyl group) is colored red. From the left: (1) formaldehyde and (2) its trimer 1,3,5-trioxane , (3) acetaldehyde and (4) its enol vinyl alcohol , (5) glucose (pyranose form as α- D -glucopyranose), (6) the flavorant cinnamaldehyde , (7) retinal , which forms with opsins photoreceptors , and (8) the vitamin pyridoxal .
Methanediol, also known as formaldehyde monohydrate or methylene glycol, is an organic compound with chemical formula CH 2 (OH) 2. It is the simplest geminal diol . In aqueous solutions it coexists with oligomers (short polymers).
Phenol-formaldehyde resins, as a group, are formed by a step-growth polymerization reaction that can be either acid- or base-catalysed. Since formaldehyde exists predominantly in solution as a dynamic equilibrium of methylene glycol oligomers , the concentration of the reactive form of formaldehyde depends on temperature and pH.