P. Eskola — Silicates of Strontium and Barium. 373 



Table XI. 



Compositions and temperatures in the systems 



CaO— SL, Sr0 2 , and BaO— Si0 2 . 



Tempera- Character of 



Wt. % Mol. % ture °C change 



CaO Si0 2 CaO Si0 2 

 Eutectic cristobalite (?)- 



a-CaO.SiO, 37.0 63.0 38.7 61.3 1436 Melting 



a-CaO.Si0 2 48.2 51.8 50 50 1540 Melting 



Eutectic a -CaO.SiO.,-3CaO. 



2SiOo 54.5 45.5 56.3 43.7 1455 Melting 



3Ca0.2SiO, 58.2 41.8 60 40 1475 Decomposition 



Invar, pt. 3Ca0.2SiO,- 



2CaO.SiOo 55.5 44.5 57.3 42.7 1475 Melting 



2CaO.SiO, 65.0 35.0 66.7 33.3 2130 Melting 



3CaO.SiO, 73.6 26.4 75 25 1900 Decomposition 



Eutectic 2CaO.SiO,-CaO.. 67.5 32.5 69.1 30.9 2065 Melting 



CaO 100 — 100 — 2570 Melting 



SrO Si0 2 SrO Si0 2 



Eutectic tridymite-SrO.SiO, 46.5 53.5 33.6 66.4 1358 Melting 



SrO.SiO, 63.2 36.8 50 50 1578 Melting 



Eutectic SrO.SiO,-2SrO. 



SiO, 65.5 34.5 52.5 47.5 1545 Melting 



2SrO.SiO, 77.5 22.5 66.7 33.3 



Eutectic 2SrO.SKX-SrO.. — — 



SrO 100 — 100 — 



BaO Si0 2 BaO Si0 2 

 Eutectic tridymite-BaO. 



2SiO, 47 53 25.9 74.1 1374 Melting 



Ba0.2SiOo 56 44 33.3 66.7 1420 Melting 



2Ba0.3Si6 2 62.9 37.1 40 60 1450 Melting 



Eutectic 2Ba0.3Si0 2 -BaO. 



SiO, 65 35 57.8 42.2 1437 Melting 



BaO.S~iO, 71.8 28.2 50 50 1604 Melting 



Eutectic BaO.SiO,-2BaO. 



SiO, 74.5 25.5 53.5 46.5 1551 Melting 



2BaO.SiO, 83.6 16.4 66.7 33.3 



Eutectic 2BaO.SiO,-BaO . . — — — — 



BaO 100 — 100 — 



the compounds BaO, 2BaO. 

 Ba0.2SiO„, and SiOo have 



In the system BaO-Si0 2 

 Si0 2 , BaO.Si0 2 , 2Ba0.3Si0 2 , 

 been found. 



Of these compounds the dibarium trisilicate, 2BaO. 

 3Si0 2 , and the barium disilicate, Ba0.2Si0 2 , showed 

 very remarkable behavior, being isomorphous, of ortho- 

 rhombic symmetry, and forming a complete series of solid 

 solutions. The melting diagram of this series belongs 

 to Bakhuis Roozeboom's type 1, without maximum or 



