The metals may be arranged in a series according to their power of displacing one another in salt solutions, thus Cs, Rb, K, Na, Mg, Al, Mn, Zn, Cd, Tl, Fe, Co, Ni, Sn, Pb, (H), Sb, Bi, As, Cu, Hg, Ag, Pd, Pt, Au.
Group I.: the alkali metals Li, Na, K, Rb, Cs, and also Ag, monovalent; Cu, monovalent and divalent; Au, monovalent and trivalent.
K, Na, Cs, Rb, Li; Tl, Ag.
How otherwise are we to explain such Hebraisms (or Syriacisms) as Evui pEEC rb g Xacov E ct ro (§ 9), ov elir€v.
Thus f (= 4-rb 2;JJ Z dY (e r) dx dy dz.
Zirconium also forms double sulphates of the type Zr203(S04M)2 nH20, where M =K, Rb, Cs, and n=8 for K, 15 for Rb, 11 for Cs (Rosenheim and Frank, Ber., 1905, 38, p. 812).
'SA N1; ` Neah?., s,; rb b'r ` D o ?utr?
As each of the four books is sometimes called 'AvOoXoycov, it is probable that this name originally belonged to the entire work; the full title, as we know from Photius, was 'EKXorywv a1r049Eryµ6trwv uiroOrpc&v f3c(3Aia rb-rapa (Four Books of Extracts, Sayings and Precepts).
Hydrogen combines with fluorine, even at very low temperatures, with great violence; it also combines with carbon, at the temperature of the electric arc. The alkali metals when warmed in a current of hydrogen, at about 360° C., form hydrides of composition RH(R = Na, K, Rb, Cs), (H.
MPV/RB = loge(p'/p"), which corresponds with the effect of hydrostatic pressure, and is equivalent to the assumption that the vapour-pressure of the solution at the bottom of the column under pressure P must be equal to that of the pure solvent.
RUBIDIUM [[[symbol]] Rb, atomic weight 85.45 (0= 16)], a metallic element belonging to the group of the alkali metals.
It rapidly dissociates when heated in vacuo to 300° C. The existence of the oxide Rb 2 0 appears to be doubtful, the results of Erdmann and Kothner (loc. cit.) pointing to the formation of Rb0 2 by the direct union of the metal with dry oxygen.
The normal sulphide, Rb 2 S 4H 2 O, is colourless, and when heated in aqueous solution with the requisite amount of sulphur is transformed into the yellow tetrasulphide, Rb 2 S 4.2H 2 O.
Ot t: r S: rB?Ento English Miles g 60 70 So L He en Tillamo?.v9?°-'"'f °.
A pentasulphide, Rb 2 S 5, which crystallizes in red prisms melting at 223° C., is also obtained by the direct union of the normal sulphide with sulphur.
When heated in a current of hydrogen it is transformed into the colourless disulphide, whilst if the heating be carried out in a current of nitrogen it yields the trisulphide, Rb 2 S 3 H 2 0.