The vibrations of the MgO crystal structure and its infra-red absorption spectrum

1961 ◽  
Vol 54 (5) ◽  
pp. 223-232
Author(s):  
C. V. Raman
1978 ◽  
Vol 42 (323) ◽  
pp. 361-368 ◽  
Author(s):  
R. A. Eggleton ◽  
B. W. Chappell

SummaryFull chemical analysis, cell dimensions, γ refractive index, density, and infra-red absorption spectrum have been determined for fourteen stilpnomelanes. Coupled with data from previously described material and electron probe analyses of three further samples, the new information shows that γ = 1·616+0·0047 Fe3+ −0·0037 Mg; substitution of Mn for Fe appears to have little effect on γ. For ferrostilpnomelane, D = 2·85−0·011 Mg, for ferristilpnomelane, D = 2·89−0·011 Mg. Cell dimensions clearly distinguish ferro-, ferri-, and man-ganstilpnomelanes; for ferri-stilpnomelane a = 22·03−0·00446 Mg−0·00786 Fe3+ (Å). A convenient approximation to the structural formula using a ⅛ subcell, is K0·6(Mg, Fe2+Fe3+)6Si8Al(O,OH)27 2–4 H2O.


1964 ◽  
Vol 20 (8) ◽  
pp. 1289-1293 ◽  
Author(s):  
C. Degani ◽  
M. Halmann ◽  
I. Laulicht ◽  
S. Pinchas

1982 ◽  
Vol 46 (341) ◽  
pp. 453-457 ◽  
Author(s):  
R. J. Hill ◽  
J. H. Canterford ◽  
F. J. Moyle

AbstractEuhedral crystals of the low-temperature mineral lansfordite, MgCO3 · 5H2O, have been prepared from saturated magnesium bicarbonate solutions at temperatures below 10°C. The crystals are monoclinic P21/a with a = 12.4758(7), b = 7.6258(4), c = 7.3463(6)Å, β = 101.762(6)°, V = 684.24Å3, Dcalc. = 1.693 g cm−3, Dobs. = 1.70(1) g m−3. At room temperature, the crystals slowly effloresce to produce pseudomorphs of nesquehonite, MgCO3 · 3H2O. Dehydration is complete at 300°C, with decarbonation taking place in the interval to 560°C. A new X-ray powder diffraction pattern is presented, and details of the infra-red absorption spectrum are discussed.


1940 ◽  
Vol 8 (3) ◽  
pp. 229-232 ◽  
Author(s):  
Ralph G. Owens ◽  
E. F. Barker

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