Boron!

Boron is a chemical element with symbol B and atomic number 5. It is a low-abundance element in both the Solar system and the Earth's crust and is concentrated on Earth by the water-solubility of its more common naturally occurring compounds, the borate minerals. These are mined industrially as evaporites, such as borax and kernite. The largest proven boron deposits are in Turkey, which is also the largest producer of boron minerals.

This rare element is a metalloid; which means that it can can act both as an acid and a base, and it also behaves as a semiconductor.  Boron never occurs in a pure state in the wild, and can only be purified with difficulty by chemists. Boron is a poor conductor of electricity, and is fairly non-reactive, although it is water soluble. The most common uses for boron-containing compounds includes a bleach for clothing, a swimming pool disinfectant and to produce green flames.

About half of global consumption of boron compounds is as additives for glass fibres in boron-containing fibreglass used for insulation or as structural materials. The next leading use is to make boron polymers and ceramics, that play specialised roles as high-strength lightweight structural and refractory materials. Borosilicate glass glassware is used for its greater strength and breakage resistance (thermal shock resistance) than ordinary soda lime glass.

For more information visit:-
http://en.wikipedia.org/wiki/Boron
http://www.theguardian.com/science/punctuated-equilibrium/2011/mar/11/1

The amazing properties of Borosilicate Glass

Borosilicate glass is a type of glass with the main glass-forming constituents silica and boron oxide. Borosilicate glasses are known for having very low coefficients of thermal expansion (~3 × 10⁻⁶ /°C at 20°C), making them resistant to thermal shock, more so than any other common glass. Such glass is less subject to thermal stress and is commonly used for the construction of reagent bottles, flasks, beakers and many other laboratory glassware items. Borosilicate glass is sold under such trade names as Pyrex, Schott & Simax.

 

Borosilicate glass was first developed by German glassmaker Otto Schott in the late 19th century and sold under the brand name "Duran" in 1893. After Corning Glass Works introduced Pyrex in 1915, the name became a synonym for borosilicate glass in the English-speaking world.

Chemical Properties
Borosilicate glass has a very high resistance to attack from water, acids, salt solutions, halogens and organic solvents. Only hydrofluoric acid, hot concentrated phosphoric acid and strong alkaline solutions cause appreciable corrosion of the glass.

Hydrolytic resistance For many applications, it is important that laboratory glassware has excellent hydrolytic resistance; e.g. during steam sterilisation procedures, where repeated exposure to water vapour at high temperature can leach out alkali (Na+) ions. Pyrex borosilicate glass for example has a relatively low alkali metal oxide content and consequently a high resistance to attack from water. Pyrex fits into Class 1 of glasses for hydrolytic resistance according to ISO 719 (98°C) and ISO 720 (121°C).

Acid resistance
Glasses with a high percentage weight of silica (SiO2) are less likely to be attacked by acids. Pyrex borosilicate glass is over 80% silica and therefore remarkably resistant to acids (with the exception of hot concentrated phosphoric acid and hydrofluoric acid). Glass is separated into 4 acid resistance classes and Pyrex corresponds to Class 1 in accordance with DIN 12116 and meets the requirements of ISO 1776.

Alkali resistance
Alkaline solutions attack all glasses and Pyrex can be classified as moderately resistant. The alkali resistance of Pyrex borosilicate glass meets Class 2 requirements as defined by ISO 695 and DIN 52322.

High usage temperature

           

The maximum permissible operating temperature for DURAN® borosilicate glass is 500 °C. Above a temperature of 525 °C the glass begins to soften and above a temperature of 860 °C it changes to the liquid state.

DURAN® can be cooled down to the maximum possible negative temperature and is therefore suitable for use with liquid nitrogen (approx. – 196 °C). During such use/ freezing. In general DURAN® products are recommended for use down to – 70 °C. During thawing ensure that the temperature difference does not exceed 100 K.

 

The link below shows how Duran glass is made
http://www.duran-group.com/en/about-duran/how-duran-is-made.html

For more information visit
http://www.scilabware.com/Glass_technical/
http://www.duran-group.com/en/about-duran/duran-properties.html
http://en.wikipedia.org/wiki/Borosilicate_glass