Germanium is a chemical element; it has symbol Ge and atomic number 32. It is lustrous, hard-brittle, grayish-white and similar in appearance to silicon. It is a metalloid in the carbon group that is chemically similar to its group neighbors silicon and tin. Like silicon, germanium naturally reacts and forms complexes with oxygen in nature.
Silicon is a chemical element; it has symbol Si and atomic number 14. It is a hard, brittle crystalline solid with a blue-grey metallic luster, and is a tetravalent metalloid and semiconductor. It is a member of group 14 in the periodic table: carbon is above it; and germanium, tin, lead, and flerovium are below it. It is relatively unreactive. Silicon is a significant element that is essential for several physiological and metabolic processes in plants. Silicon is widely regarded as the predominant semiconductor material due to its versatile applications in various electrical devices such as transistors, solar cells, integrated circuits, and others. These may be due to its significant band gap, expansive optical transmission range, extensive absorption spectrum, surface roughening, and effective anti-reflection coating.
Rutile is an oxide mineral composed of titanium dioxide (TiO2), the most common natural form of TiO2. Rarer polymorphs of TiO2 are known, including anatase, akaogiite, and brookite.
Silicon dioxide, also known as silica, is an oxide of silicon with the chemical formula SiO2, commonly found in nature as quartz. In many parts of the world, silica is the major constituent of sand. Silica is abundant as it comprises several minerals and synthetic products. All forms are white or colorless, although impure samples can be colored.
A metalloid is a chemical element which has a preponderance of properties in between, or that are a mixture of, those of metals and nonmetals. There is no standard definition of a metalloid and no complete agreement on which elements are metalloids. Despite the lack of specificity, the term remains in use in the literature.
The carbon group is a periodic table group consisting of carbon (C), silicon (Si), germanium (Ge), tin (Sn), lead (Pb), and flerovium (Fl). It lies within the p-block.
Titanium dioxide, also known as titanium(IV) oxide or titania, is the inorganic compound derived from titanium with the chemical formula TiO
2. When used as a pigment, it is called titanium white, Pigment White 6 (PW6), or CI 77891. It is a white solid that is insoluble in water, although mineral forms can appear black. As a pigment, it has a wide range of applications, including paint, sunscreen, and food coloring. When used as a food coloring, it has E number E171. World production in 2014 exceeded 9 million tonnes. It has been estimated that titanium dioxide is used in two-thirds of all pigments, and pigments based on the oxide have been valued at a price of $13.2 billion.
Fused quartz, fused silica or quartz glass is a glass consisting of almost pure silica (silicon dioxide, SiO2) in amorphous (non-crystalline) form. This differs from all other commercial glasses, such as soda-lime glass, lead glass, or borosilicate glass, in which other ingredients are added which change the glasses' optical and physical properties, such as lowering the melt temperature, the spectral transmission range, or the mechanical strength. Fused quartz, therefore, has high working and melting temperatures, making it difficult to form and less desirable for most common applications, but is much stronger, more chemically resistant, and exhibits lower thermal expansion, making it more suitable for many specialized uses such as lighting and scientific applications.
Stishovite is an extremely hard, dense tetragonal form (polymorph) of silicon dioxide. It is very rare on the Earth's surface; however, it may be a predominant form of silicon dioxide in the Earth, especially in the lower mantle.
Tellurium dioxide (TeO2) is a solid oxide of tellurium. It is encountered in two different forms, the yellow orthorhombic mineral tellurite, β-TeO2, and the synthetic, colourless tetragonal (paratellurite), α-TeO2. Most of the information regarding reaction chemistry has been obtained in studies involving paratellurite, α-TeO2.
Germanium tetrachloride is a colourless, fuming liquid with a peculiar, acidic odour. It is used as an intermediate in the production of purified germanium metal. In recent years, GeCl4 usage has increased substantially due to its use as a reagent for fiber optic production.
An optical fiber, or optical fibre, is a flexible glass or plastic fiber that can transmit light from one end to the other. Such fibers find wide usage in fiber-optic communications, where they permit transmission over longer distances and at higher bandwidths than electrical cables. Fibers are used instead of metal wires because signals travel along them with less loss and are immune to electromagnetic interference. Fibers are also used for illumination and imaging, and are often wrapped in bundles so they may be used to carry light into, or images out of confined spaces, as in the case of a fiberscope. Specially designed fibers are also used for a variety of other applications, such as fiber optic sensors and fiber lasers.
Germanium telluride (GeTe) is a chemical compound of germanium and tellurium and is a component of chalcogenide glass. It shows semimetallic conduction and ferroelectric behaviour.
Silicon monoxide is the chemical compound with the formula SiO where silicon is present in the oxidation state +2. In the vapour phase, it is a diatomic molecule. It has been detected in stellar objects and has been described as the most common oxide of silicon in the universe.
Niobium dioxide, is the chemical compound with the formula NbO2. It is a bluish-black non-stoichiometric solid with a composition range of NbO1.94-NbO2.09. It can be prepared by reducing Nb2O5 with H2 at 800–1350 °C. An alternative method is reaction of Nb2O5 with Nb powder at 1100 °C.
Silicon carbonate is a crystalline substance formed under pressure from silica and carbon dioxide. The formula of the substance is SiCO4. To produce it silicalite is compressed with carbon dioxide at a pressure of 18 Gpa and a temperature around 740 K (467 °C; 872 °F). The silicon carbonate made this way has carbonate linked to silicon by way of oxygen in unidentate, bidentate, or bridged positions. However a stable crystal structure is not formed in these conditions. The phase produced is amorphous, but it has carbon in three-fold coordination, and silicon in six-fold coordination. When decompressed, not all carbon is released as carbon dioxide. If this really exists, the substance should be dynamically stable when reduced to atmospheric pressure.
The +4 oxidation state dominates titanium chemistry, but compounds in the +3 oxidation state are also numerous. Commonly, titanium adopts an octahedral coordination geometry in its complexes, but tetrahedral TiCl4 is a notable exception. Because of its high oxidation state, titanium(IV) compounds exhibit a high degree of covalent bonding.
Germanium compounds are chemical compounds formed by the element germanium (Ge). Germanium is insoluble in dilute acids and alkalis but dissolves slowly in hot concentrated sulfuric and nitric acids and reacts violently with molten alkalis to produce germanates ([GeO
3]2−
). Germanium occurs mostly in the oxidation state +4 although many +2 compounds are known. Other oxidation states are rare: +3 is found in compounds such as Ge2Cl6, and +3 and +1 are found on the surface of oxides, or negative oxidation states in germanides, such as −4 in Mg
2Ge. Germanium cluster anions (Zintl ions) such as Ge42−, Ge94−, Ge92−, [(Ge9)2]6− have been prepared by the extraction from alloys containing alkali metals and germanium in liquid ammonia in the presence of ethylenediamine or a cryptand. The oxidation states of the element in these ions are not integers—similar to the ozonides O3−.
