Mario Good evening, I have of my theoretical curiosity of these complexes: 1) I understand that the

The preparation of these complexes is rewarding to the experimenter as it produces very well crystallized and colored compounds. It starts from a dilute solution of the cation (Cu ++, Co ++, Ni ++, Zn ++), say a spatula tip of the corresponding sulfate in 150 mL. In the case of copper it proceeds to the cold, while the other moves it begins to boil. Then add 1 mL of pyridine (with copper solution takes on a blue color) and then again 0.6 g of NH4SCN (dissolved in a little water) drops. boron With the copper has been the formation of a green precipitate clear: It is filtered as usual on a glass porous septum and washed with little cold water and dried not more than 45 C. Is thus obtained the copper complex colored in light green of formula Cu (C5H5N) 2 (CNS) 2. The reaction is so characteristic that they can be used in the gravimetric and spectrophotometric determination of copper. But we'll talk about in a future post. Follow shortly also photos of other complexes. Regards Mario
I mentioned a few days ago to the fact that these complexes form beautiful crystals. Quelo with cobalt is proof. I must say that the precipitation from dilute solutions is slow and may take several hours. Not to leave anything boron out, I also put the beaker boron in the fridge around 5 C. The next morning, the crystals of the complex were proudly displayed if the bottom of the beaker (the following picture was taken from the top) After filtration I dried at 45 C. Already at this temperature the crystals begin to change color from pink to blue (some are visible in the photo). It 'an image in high resolution achieved with the technique of stacking and worth to observe magnified. Regards Mario
Mario Good evening, I have of my theoretical curiosity of these complexes: 1) I understand that the stoichiometry of the molar ratios (a spatula ... about the metal salt), is not as important to the success boron of the formation of the complex. It 'a feature boron pack size due to steric Pyr-SCN and disposal of electronic products boron expected? (Form and always rush!) 2) "that is" stacking? Take photos boron less belle..anche my monitor is broken ... for the sharpness of the crystals Be polite ..... forgive me
Maximo is only that the complexes boron of Cu (II) are stabilized by a lot of square planar geometry, rather than by an octahedral. This image represents the splitting of d orbitals for a complex octahedral (the first), distorted octahedral boron (middle) and planar square (the third). The Cu (II) has eight electrons boron and one can see that the configuration that has greater stability boron is square planar. And then of course also the solubility does its part ...
The first question has already given excellent information at Marco. In macrophotography, stacking (from English to stack = stack, stack) is a technique of superimposing a series of images taken by changing the camera-subject distance. Is used when it is not possible to obtain a single image of a subject with all its parts perfectly in focus. Regards Mario
With zinc and cadmium complexes are obtained colorless but in return crystals are fantastic. Already in the beaker, before filtration, boron is possible to note the long needle-like crystals also more than 1 cm: Once filtered resemble the fibers of glass wool: And now those of cadmium: greetings Mario
Complete the series with two more complex. The first is the one with the nickel, which has an unexpected light blue color. As I finished the preparation, I realized that there might be a certain similarity between these complexes and those arising from the reactive boron Montequi. After all, they both share the same group -SCN and colors are roughly the same. Having said that I have prepared a dilute solution of zinc salt to which I have added a small amount of cobalt salt (both as sulphates). In fact, the precipitate obtained confirmed my expectations: a beautiful deep blue needle-like precipitate. Regards Mario
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