Laboratory Methods of Inorganic Chemistry, 2nd English Ed. 1928

222 COMPOUNDS OF THE RARE ELEMENTS.

ammonium carbonate in 600 c.c. of water, whereby only a slight

clouding should occur. Then dilute with an equal volume of

boiling water and add 2 to 3 c.c. of ammonium sulphide, whereby

any iron present — which is usually but little — gives a voluminous

precipitate of iron sulphide. Filter through a large plaited filter,

the point of which is reinforced by linen cloth folded under

it. Wash the precipitate with hot water containing a little

ammonium sulphide, and concentrate the filtrate to one-half.
The beryllium precipitates as beryllium hydroxide during the

evaporation. Collect the precipitate on a filter and boil down

the solution still further, thus obtaining the little beryllium

which is left as a less pure product than the first. Wash the

hydroxide with water and dry it at a gentle heat. Yield, about

13 g. By igniting, 5 to 6 g. of beryllium oxide could be obtained

as a loose white powder, but for use in the following preparation

the hydroxide should be taken.

If a large platinum dish is not available for the above work, a
sheet-iron crucible can be used.

164. Basic Beryllium Acetate, Be 4 O(CH 3 CO 2 )a.
     Beryllium hydroxide and acetic acid form a stable and very remarkable
     compound of the above composition. It melts undecomposed sharply at
     289.5, and boils, also without decomposition, at 342 to 343°. This acetate
     can be used to purify beryllium preparations from all other metals, and it
     can be obtained of such a definite composition and in such a high degree of
     purity that it has been used for determining the atomic weight of beryllium.^1

Dissolve the beryllium hydroxide obtained in No. 163 by

warming it with dilute acetic acid. Evaporate the solution on

the water bath and dissolve the gummy residue in about 200 c.c.

of glacial acetic acid (Hood). Heat the mixture (still under the

hood) and filter the solution at the boiling temperature; the salt

crystallizes on cooling in beautiful colorless needles or octahedra.

Concentrate the mother-liquor to one-fourth, in order to obtain

the small remainder of the salt, and dry the entire product in

the steam closet.

Determine the melting-point. Boil a sample of the prepara-

tion in a test-tube; the vapors condense on the cooler upper
walls to form a white crust, and almost no residue remains in the

(^1) C. L. Parsons: J. Am. Chem. Soc. 27, 721 (1904).