User Rating: 0 / 5

Star InactiveStar InactiveStar InactiveStar InactiveStar Inactive

Covalent bond in which electron density is symmetrically distributed.

Latest Articles

  • Use of diamonds

    Diamond is a crystalline modification of pure carbon formed in the deep interior of the Earth, in the upper mantle at depths of more than 80-100 kilometers, at exceptionally high pressure and temperature. It is the most precious stone, the hardest and most wear-resistant mineral, the most...

  • 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.

  • Protein Design: Automated protein discovery and synthesis

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

  • Varieties of garnet minerals

    The most famous type of garnet stone is pyrope (flaming). This is the "oldest of garnets", with a dense red color, similar to the grain of an edible garnet. Pyrope has a variety called rhodolite - a stone of dense pink or pink-purple color, which sometimes has the alexandrite effect and is used in...

  • 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...

Most Popular


A sample of matter composed of two or more substances, each of which retains its identity and properties.

Band of Stability

Band containing nonradioactive nuclides in a plot of number of neutrons versus atomic number.


A small, calibrated electroscope worn by laboratory personnel and designated to detect and measure incident ionizing radiation or chemical exposure.

Law of Conservation of Energy

Energy cannot be created or destroyed, it may be changed from one form to another.

Differential Thermal Analysis (DTA)

A technique for observing the temperature, direction, and magnitude of thermally induced transitions in a material by heating/cooling a sample and comparing its temperature with that of an inert reference material under similar conditions.


The study of the energy transfers accompanying physical and chemical processes.

Absolute Entropy (of a substance)

The increase in the entropy of a substance as it goes from a perfectly ordered crystalline form at 0 °K (where its entropy is zero) to the temperature in question.

Entropy is a measure of the “dilution” of thermal energy.

Avogadro's Law

At the same temperature and pressure, equal volumes of all gases contain the same number of molecules.

Inhibitory Catalyst

An inhibitor, a catalyst that decreases the rate of reaction.

Activation Energy

Amount of energy that must be absorbed by reactants in their ground states to reach the transition state so that a reaction can occur. In other words, activation energy is the minimum energy required for a chemical reaction to occur.