A silver halide is one of the chemical compounds that can form between the element silver (Ag) and one of the halogens. In particular, bromine (Br), chlorine (Cl), iodine (I) and fluorine (F) may each combine with silver to produce silver bromide (AgBr), silver chloride (AgCl), silver iodide (AgI), and four forms of silver fluoride, respectively.
A clathrate is a chemical substance consisting of a lattice that traps or contains molecules. The word clathrate is derived from the Latin clathratus, meaning 'with bars, latticed'. Most clathrate compounds are polymeric and completely envelop the guest molecule, but in modern usage clathrates also include host–guest complexes and inclusion compounds. According to IUPAC, clathrates are inclusion compounds "in which the guest molecule is in a cage formed by the host molecule or by a lattice of host molecules." The term refers to many molecular hosts, including calixarenes and cyclodextrins and even some inorganic polymers such as zeolites.
Thiourea is an organosulfur compound with the formula SC(NH2)2 and the structure H2N−C(=S)−NH2. It is structurally similar to urea, except that the oxygen atom is replaced by a sulfur atom ; however, the properties of urea and thiourea differ significantly. Thiourea is a reagent in organic synthesis. Thioureas are a broad class of compounds with the general structure R2N−C(=S)−NR2.
Copper(I) iodide is the inorganic compound with the formula CuI. It is also known as cuprous iodide. It is useful in a variety of applications ranging from organic synthesis to cloud seeding.
Sulfathiazole is an organosulfur compound used as a short-acting sulfa drug. Formerly, it was a common oral and topical antimicrobial, until less toxic alternatives were discovered.
In organic chemistry, thioureas are members of a family of organosulfur compounds with the formula S=C(NR2)2 and structure R2N−C(=S)−NR2. The parent member of this class of compounds is thiourea. Substituted thioureas are found in several commercial chemicals.
Thallium(I) sulfide, Tl2S, is a chemical compound of thallium and sulfur. It was used in some of the earliest photo-electric detectors by Theodore Case who developed the so-called thalofide (sometimes spelt thallofide) cell, used in early film projectors. Case described the detector material as consisting of thallium, oxygen and sulfur, and this was incorrectly described by others as being thallium oxysulfide, which incidentally is a compound that is not known. Case's work was then built on by R.J. Cashman who recognised that the controlled oxidation of the Tl2S film was key to the operation of the cell. Cashman's work culminated in the development of long wave infrared detectors used during the Second World War. Reliable Tl2S detectors were also developed in Germany at the same time.
Tl2S is found in nature as the mineral carlinite which has the distinction of being the only sulfide mineral of thallium that does not contain at least two metals. Tl2S has a distorted anti-CdI2 structure.
Tl2S can be prepared from the elements or by precipitating the sulfide from a solution of thallium(I), e.g. the sulfate or nitrate. Thin films have been deposited, produced from a mixture of citratothallium complex and thiourea. Heating the film in nitrogen at 300°C converts all the product into Tl2S
Thiosemicarbazide is the chemical compound with the formula H2NC(S)NHNH2. A white, odorless solid, it is related to thiourea (H2NC(S)NH2) by the insertion of an NH center. They are commonly used as ligands for transition metals. Many thiosemicarbazides are known. These feature an organic substituent in place of one or more H's of the parent molecule. 4-Methyl-3-thiosemicarbazide is a simple example.
Sulfene is an extremely reactive chemical compound with the formula H2C=SO2. It is the simplest member of the sulfenes, the group of compounds which are S,S-dioxides of thioaldehydes and thioketones, and have the general formula R2C=SO2.
Tellurium iodide is an inorganic compound with the formula TeI. Two forms are known. Their structures differ from the other monohalides of tellurium. There are three subiodides of tellurium, α-TeI, β-TeI, and Te2I, and one tellurium tetraiodide.
Selenourea is the organoselenium compound with the chemical formula Se=C(NH2)2. It is a white solid. This compound features a rare example of a stable, unhindered carbon-selenium double bond. The compound is used in the synthesis of selenium heterocycles. Selenourea is a selenium analog of urea O=C(NH2)2. Few studies have been done on the compound due to the instability and toxicity of selenium compounds. Selenourea is toxic if inhaled or consumed.
Thiourea dioxide or thiox is an organosulfur compound that is used in the textile industry. It functions as a reducing agent. It is a white solid, and exhibits tautomerism.
Dithiobiuret is an organosulfur compound with the formula HN(C(S)NH2)2. It is a colourless solid that is soluble in warm water and polar organic solvents. It is a planar molecule with short C-S and C-N distances (1.69, 1.38 Å, resp.) indicative of multiple C-S and C-N bonding.
N,N′-Di-n-butylthiourea is an organic compound with the formula S=C(N(H)Bu)2 (Bu = butyl). A symmetrical N,N′-dialkyl thiourea derivative, it is a white solid. Like other thiourea derivatives, it features a planar core. The C=S bond distance is 1.712(2) Å, while C−N distances are in range of 1.33 to 1.46 Å. Molecules of this compound exhibit syn-anti conformation.
4-Amino-3-hydrazino-5-mercapto-1,2,4-triazole is an organic compound with the formula SC2N3H(NH2)(N2H3). The compound consists of a 1,2,4-triazole heterocycle with three functional groups: amine, thioamide and hydrazyl. X-ray crystallography shows that this molecule is polar but with a C=S double bond. It is prepared by the reaction of hydrazine with thiourea:
2-Imidazolidinethione is the organosulfur compound with the formula C2H2(NH)2C=S. It is a cyclic unsaturated thiourea with a short C=S bond length of 169 pm. The compound is often referred to as 2-mercaptoimidazole, which is a tautomer that is not observed. The compound forms a variety of metal complexes. In terms of bonding and reactivity, 2-imidazolidinethione is similar to mercaptobenzimidazole.
Neodymium(III) iodide is an inorganic salt of iodine and neodymium with the formula NdI3. Neodymium uses the +3 oxidation state in the compound. The anhydrous compound is a green powdery solid at room temperature.
Nickel(II) perchlorate is a inorganic compound with the chemical formula of Ni(ClO4)2, and it is a strong oxidizing agent. Its colours are different depending on water. For example, the hydrate forms cyan crystals, the pentahydrate forms green crystals, but the hexahydrate (Ni(ClO4)2·6H2O) forms blue crystals.
Praseodymium(III) iodide is an inorganic salt, consisting of the rare-earth metal praseodymium and iodine, with the chemical formula PrI3. It forms green crystals. It is soluble in water.
Urea can crystallise with other compounds. These can be called urea adducts or if a solvent is involved, a urea solvate, and the process is called urea extraction crystallization. Urea can also be a neutral ligand if it is coordinated to a central metal atom. Urea can form hydrogen bonds to other oxygen and nitrogen atoms in the substance it crystallises with. This stiffens the solid and raises the melting point. T
