How To Clean Celtic Charriol Bracelet

Davidoffski and salts with an alter ego. Part 3 - tin fluoride (II). Mgr

Angielski version of this post is located in. "In Angielski" section!)

Tin and its compounds are of interest to me for a very long time. We can call those interested in a kind of "chemical fetish", the same is true in my case with some other elements and their derivatives (eg, selenium, antimony, gold and mercury). It is difficult even so by the end justify, you can see "beauty" of certain elements throw at me more charm;) (the largest cast of course beautiful women ^ ^).

fluoride tin (II) is all the more interesting relationship, that some of us may have it in their mouth every day! But more about that in a moment, first a short description SNF ₂ . Fluoride tin (II) is a colorless crystalline body which melts at 213 ^of C. Standing SNF ₂ adopt a distorted rutile structure, in which tetramers Sn ₄ F ₈ are joined by a bridging fluoride. Each atom Sn is associated with six fluorine atoms to form systems with strongly deformed octahedral geometry. In the gas phase SNF ₂ is a monomer with an angular structure, are also present dimers and trimers ( Sn ₂ F ₄ , Sn ₃ F ₆ ), but their share in the mixture decreases with increasing temperature. SNF ₂ dissolves very well in water, which eventually hydrolyzed. In aqueous solutions, in the presence of fluoride ions to form complex anions, such as [SNF ₃ ] ^- , [Sn ₂ F ₅ ] ^- and [SNF ₂ (OH ₂ )] . The existence of such objects should not surprise us, however, SNF ₂ a Lewis acid;) dominating the individual is [SNF ₃ ] ^- (stable anion on the construction of a pyramid, Figure 1). When there is a shortage of fluoride, may form complex anions such as bridge [F ₂ Sn ( μ -F) SNF ₂ ] ^- (Fig. 2).

Figure 1

When crystallized SNF ₂ from aqueous solutions containing NaF , produced individuals such as Na [Sn ₂ F ₅ ] and On ₄ [Sn ₃ F ₁₀ ]. building complex anions forming these compounds, is shown in Figure 2 and Figure 3

Figure 2

Figure 3

If the potassium cations are present, there is a hydrate K [SNF ₃ ] × 1/2H ₂ O contains in its structure to build a polyanion shown in Figure 4 Independent anions [SNF ₃ ] ^- are up for it in [NH ₄ ] [SNF ₃ ] and Ca [ SNF ₃ ] ₂

Figure 4

It was hard for me to find something that will satisfy organików chemists on the link. I managed, however, find an example;) SNF ₂ with fluoride is converted to trichloromethyl ethers trifluoromethyl ethers:

Let's go back However, what I wrote at the outset. Writing about the fact that some of you may have fluoride in the mouth of tin (II), I was thinking of toothpaste or mouthwash mouth. For the first time SNF ₂ appeared in toothpaste Fluoristan (now the Crest brand , companies Procter & Gamble, Crest toothpaste sold in Europe under the name Blend-A-Med ), introduced in 1955 and was its main ingredient until 1981, when he changed it to sodium monofluorophosphate (Fig. 5).

Figure 5

Recently, Crest introduced back SNF 2, this time to paste Crest Pro-Health . Stannous fluoride, in addition to act as a fluorujący, acts as an antibacterial, prevents tooth decay, gingivitis and plaque formation of the wafer, which distinguishes this compound from NaF, because it only protects against decay. What's more, SNF ₂ can be used in a mixture with calcium-containing abrasives because they do not block its biological activity, as happens in the case of NaF. Fluoride toothpaste tin (II) have been warning about the possibility of the appearance of stains on your teeth, but they contain abrasive additives, removing this effect ( silica and sodium hexametaphosphate (Fig. 6).

Figure 6

preparation mouthwash and toothpaste Meridol also contain SNF 2, together with the amine called Olaflur (difluoride N, N, N '-tris (2 - hydroxyethyl) - N '-oktadecylopropano-1 ,3-diamoniowy , Figure 7).

Figure 7