A borate is any of a range of boron oxyanions, anions containing boron and oxygen, such as orthoborate BO3−3, metaborate BO−2, or tetraborate B4O2−7; or any salt of such anions, such as sodium metaborate, Na+[BO2]− and borax (Na+)2[B4O7]2−. The name also refers to esters of such anions, such as trimethyl borate B(OCH3)3 but they are alkoxides.
Anticonvulsants are a diverse group of pharmacological agents used in the treatment of epileptic seizures. Anticonvulsants are also increasingly being used in the treatment of bipolar disorder and borderline personality disorder, since many seem to act as mood stabilizers, and for the treatment of neuropathic pain. Anticonvulsants suppress the excessive rapid firing of neurons during seizures. Anticonvulsants also prevent the spread of the seizure within the brain.
A silanol is a functional group in silicon chemistry with the connectivity Si–O–H. It is related to the hydroxy functional group (C–O–H) found in all alcohols. Silanols are often invoked as intermediates in organosilicon chemistry and silicate mineralogy. If a silanol contains one or more organic residues, it is an organosilanol.
Pyrene is a polycyclic aromatic hydrocarbon (PAH) consisting of four fused benzene rings, resulting in a flat aromatic system. The chemical formula is C16H10. This yellow-green solid is the smallest peri-fused PAH. Pyrene forms during incomplete combustion of organic compounds.
Status epilepticus (SE), or status seizure, is a medical condition consisting of a single seizure lasting more than 5 minutes, or 2 or more seizures within a 5-minute period without the person returning to normal between them. Previous definitions used a 30-minute time limit. The seizures can be of the tonic–clonic type, with a regular pattern of contraction and extension of the arms and legs, or of types that do not involve contractions, such as absence seizures or complex partial seizures. Status epilepticus is a life-threatening medical emergency, particularly if treatment is delayed.
In organosilicon chemistry, a siloxane is an organic compound containing a functional group of two silicon atoms bound to an oxygen atom: Si−O−Si. The parent siloxanes include the oligomeric and polymeric hydrides with the formulae H[OSiH2]nOH and [OSiH2]n. Siloxanes also include branched compounds, the defining feature of which is that each pair of silicon centres is separated by one oxygen atom. The siloxane functional group forms the backbone of silicones [−R2Si−O−SiR2−]n, the premier example of which is polydimethylsiloxane (PDMS). The functional group R3SiO− is called siloxy. Siloxanes are manmade and have many commercial and industrial applications because of the compounds’ hydrophobicity, low thermal conductivity, and high flexibility.
Hydroxyapatite is a naturally occurring mineral form of calcium apatite with the formula Ca5(PO4)3(OH), often written Ca10(PO4)6(OH)2 to denote that the crystal unit cell comprises two entities. It is the hydroxyl endmember of the complex apatite group. The OH− ion can be replaced by fluoride or chloride, producing fluorapatite or chlorapatite. It crystallizes in the hexagonal crystal system. Pure hydroxyapatite powder is white. Naturally occurring apatites can, however, also have brown, yellow, or green colorations, comparable to the discolorations of dental fluorosis.
Ionic radius, rion, is the radius of a monatomic ion in an ionic crystal structure. Although neither atoms nor ions have sharp boundaries, they are treated as if they were hard spheres with radii such that the sum of ionic radii of the cation and anion gives the distance between the ions in a crystal lattice. Ionic radii are typically given in units of either picometers (pm) or angstroms (Å), with 1 Å = 100 pm. Typical values range from 31 pm (0.3 Å) to over 200 pm (2 Å).
Primidone, sold under various brand names, is a barbiturate medication that is used to treat partial and generalized seizures and essential tremors. It is taken by mouth.
Silyl ethers are a group of chemical compounds which contain a silicon atom covalently bonded to an alkoxy group. The general structure is R1R2R3Si−O−R4 where R4 is an alkyl group or an aryl group. Silyl ethers are usually used as protecting groups for alcohols in organic synthesis. Since R1R2R3 can be combinations of differing groups which can be varied in order to provide a number of silyl ethers, this group of chemical compounds provides a wide spectrum of selectivity for protecting group chemistry. Common silyl ethers are: trimethylsilyl (TMS), tert-butyldiphenylsilyl (TBDPS), tert-butyldimethylsilyl (TBS/TBDMS) and triisopropylsilyl (TIPS). They are particularly useful because they can be installed and removed very selectively under mild conditions.
Prazepam is a benzodiazepine derivative drug developed by Warner-Lambert in the 1960s. It possesses anxiolytic, anticonvulsant, sedative and skeletal muscle relaxant properties. Prazepam is a prodrug for desmethyldiazepam which is responsible for the therapeutic effects of prazepam.
Organosilicon chemistry is the study of organometallic compounds containing carbon–silicon bonds, to which they are called organosilicon compounds. Most organosilicon compounds are similar to the ordinary organic compounds, being colourless, flammable, hydrophobic, and stable to air. Silicon carbide is an inorganic compound.
Pheneturide, also known as phenylethylacetylurea, is an anticonvulsant of the ureide class. Conceptually, it can be formed in the body as a metabolic degradation product from phenobarbital. It is considered to be obsolete and is now seldom used. It is marketed in Europe, including in Poland, Spain and the United Kingdom. Pheneturide has a similar profile of anticonvulsant activity and toxicity relative to phenacemide. As such, it is only used in cases of severe epilepsy when other, less-toxic drugs have failed. Pheneturide inhibits the metabolism and thus increases the levels of other anticonvulsants, such as phenytoin.
Trimethylsilanol (TMS) is an organosilicon compound with the formula (CH3)3SiOH. The Si centre bears three methyl groups and one hydroxyl group. It is a colourless volatile liquid.
A silsesquioxane is an organosilicon compound with the chemical formula [RSiO3/2]n. Silsesquioxanes are colorless solids that adopt cage-like or polymeric structures with Si-O-Si linkages and tetrahedral Si vertices. Silsesquioxanes are members of polyoctahedral silsesquioxanes ("POSS"), which have attracted attention as preceramic polymer precursors to ceramic materials and nanocomposites. Diverse substituents (R) can be attached to the Si centers. The molecules are unusual because they feature an inorganic silicate core and an organic exterior. The silica core confers rigidity and thermal stability.
Disiloxane has the chemical formula Si
2H
6O. It is the simplest known siloxane with hydrogen only R groups. The molecule contains six equivalent Si−H bonds and two equivalent Si−O bonds. Disiloxane exists as a colorless, pungent gas under standard conditions. However, it is generally safe for human use as evidence in its widespread use in cosmetics. It is also commonly known as disilyl ether, disilyl oxide, and perhydrodisiloxane
Direct bonding, or fusion bonding, describes a wafer bonding process without any additional intermediate layers. The bonding process is based on chemical bonds between two surfaces of any material possible meeting numerous requirements. These requirements are specified for the wafer surface as sufficiently clean, flat and smooth. Otherwise unbonded areas so called voids, i.e. interface bubbles, can occur.
Silanization of silicon and mica is the coating of these materials with a thin layer of self assembling units.
The sulfate carbonates are a compound carbonates, or mixed anion compounds that contain sulfate and carbonate ions. Sulfate carbonate minerals are in the 7.DG and 5.BF Nickel-Strunz groupings.
The sulfate fluorides are double salts that contain both sulfate and fluoride anions. They are in the class of mixed anion compounds. Some of these minerals are deposited in fumaroles.
