. Journal of applied microscopy and laboratory methods. t trace of acid is apt to preventthe separation of the characteristic crystals. If no crystals appear after a short time, add afragment of sodium or ammonium acetate. When calcium or strontium are present thecharacteristic crystal forms of barium oxalate willnot be obtained. Recourse may then be had to testing in dilute nitric acid. From nitric acid solutions the barium salt will notseparate, while the oxalates of calcium and strontium will slowly crystallize intheir usual form. After allowing sufficient time for the complete separation o
. Journal of applied microscopy and laboratory methods. t trace of acid is apt to preventthe separation of the characteristic crystals. If no crystals appear after a short time, add afragment of sodium or ammonium acetate. When calcium or strontium are present thecharacteristic crystal forms of barium oxalate willnot be obtained. Recourse may then be had to testing in dilute nitric acid. From nitric acid solutions the barium salt will notseparate, while the oxalates of calcium and strontium will slowly crystallize intheir usual form. After allowing sufficient time for the complete separation ofcalcium and strontium, draw off, concentrate the solution, and add sodiumacetate. Barium oxalate now appears, usually in the form of rosettes of thinprisms. Barium oxalate, like the oxalates of calcium and strontium, assumes differentcrystal forms according as the test drop is hot or cold. Hot solutions give riseto the production of strongly polarizing orthorhombic plates. Since, in order to facilitate the separation of barium oxalate, sodium acetate. 1296 Journal of Applied Microscopy has been added, it is well to bear in mind that there is danger of interferencefrom members of the magnesium group. Boric acid present in the test drop may prevent the formation of characteristiccrystals of barium oxalate. Although chlorides of iron and aluminum have, as has been stated, no dele-terious iniiuence on the precipitation of the oxalates of calcium and strontium,we meet in the case of barium with a most interesting and remarkable to the formation of a double oxalate, instead of the forms shown in , there are now obtained tufts and bunches of very long, fine, curving, hair-likecrystals of exceedingly characteristic appearance. The chemical compositionand formula of this compound is not yet clear. In order to obtain this interest-ing compound, proceed as follows: To the test drop containing barium, addferric chloride in sufficient amount to impart a faint but disti
Size: 1277px × 1956px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1900, booksubjectmicrosc, bookyear1901
