Star InactiveStar InactiveStar InactiveStar InactiveStar Inactive
 

Any kind of matter all specimens of which have the same chemical composition and physical properties.

 

Latest Articles

  • The most expensive metal in the world

    Do you think the most expensive metal is gold? No! On earth there are more valuable metals. But we need to divide the value of metals that occur in nature, and metals - isotopes, which are obtained in special laboratories. Let’s look at natural metals first.

  • What are Compound Microscopes?

    Most of the microscopes used today are compound. A compound microscope features two or more lenses. A hollow cylinder called the tube connects the two lenses. The top lens, the one people look through, is called the eyepiece. The bottom lens is known as the objective lens. Below the two lenses is...

  • Gas of rotten eggs

    If you happen to break a rotten egg, then you know the smell of hydrogen sulfide, because the stench of the spoiled egg depends on of its presence in rotting protein substances.

  • Features of the Scanning Tunneling Microscope

    The scanning tunneling microscope (STM) invented by Heinrich Rohrer and Gerd Binnig in the 1980s still manages to do a great job today and competes with more advanced microscope types. The scanning tunneling microscope is used for studying the surface atoms that are found on various materials. The...

  • Protein Design: Automated protein discovery and synthesis

    In this paper I describe (theoretically) the method(s) of automated protein discovery and synthesis.



Most Popular

Dipole Moment

The product of the distance separating opposite charges of equal magnitude of the charge, a measure of the polarity of a bond or molecule, a measured dipole moment refers to the dipole moment of an entire molecule.

Effective Nuclear Charge

The nuclear charge experienced by the outermost electrons of an atom, the actual nuclear charge minus the effects of shielding due to inner-shell electrons.
Example: Set of dx2-y2 and dz2 orbitals, those d orbitals within a set with lobes directed along the x-, y-, and z-axes.

Conjugated Double Bonds

Double bonds that are separated from each other by one single bond -C=C-C=C-.

Compressed Gas

A gas or mixture of gases having, in a container an absolute pressure exceeding 40 psi at 21.1°C (70°F)

Eluate

Solvent (or mobile phase) which passes through a chromatographic column and removes the sample components from the stationary phase.

Covalent Compounds

Compounds containing predominantly covalent bonds.

Octahedral

A term used to describe molecules and polyatomic ions that have one atom in the center and six atoms at the corners of a octahedron.

Lewis Acid

Any species that can accept a share in an electron pair.

How to make crystal glass

From history we know that the idea of creating crystal belongs to the British: they were the first to add lead oxides to the charge material, and as a result got glass with unusual “voice”, transparency and sparkling faces. Classical crystal contains 24% of lead oxide, but there are products with a higher content of up to 30%.

Allotropic Modifications (Allotropes)

Different forms of the same element in the same physical state.