54.121:543 , , [email protected] - III , III , , . Solubility and amphotericity, thermodynamic calculation, oxides and hydroxides of IIIB group, aqueous media. [1, 2] . III III . III [3, 4]. , , , , , , ( )3. Sc(OH)3 c α-ScOOH [5]. ( [6] )3 - . . 2 3 , 156 , [5, 6]. - [5, 6]. III - , . [5−7]. - , [6] (III). , « , » , La2O3 · n H2O [5, 6]. , 0,5 (∆G = +22 2 3( ) + 1,5 ( )= 2 ( )3( ) ) ScO1,5 . III )3 (∆G = −34 ( YO1,5 −101 LaO1,5). , ( - )3 1,5 )3( ) ⇄ ( ( )+ 1.5( ) + 1,5 Ks = ( 3+ ), ( − 2 =a( 3+ ( )+3 ( )⇄ 2 3+ ( )⇄ 3+ 3+ )– Ks − ( ), − ( )+3 3+ ) · a3 ( (0,5Sc2O3), − ( )+ − ( ), (1) ( ), ) = const(T), − . . (1) ∆Gf ∆Gf [1]. [8]. 298 [4, 7]. , 157 3,1, 4,8, 6,2 = d ln [M 3+] / d ln CM [9] Sc2O3, Sc(OH)3, Y(OH)3 6,7. =1 s CM K S0 3 f M 3 f OH Ks f (M3+), f (OH−) – 0 = 1, 1, 2, 3, 4 – 2+ , ( )2+, ( )3 ( )4− [3, 9]. (III) . Sc2(OH)24+, Sc3(OH)54+ , Y3(OH)54+ La5( [9, c. 23] La(OH)3 4 ( Sc(OH)3 3,7(∆lg s = 0.02) 19 i OH i3 n i0 La(OH)3 , 3+ (1); − ; La2OH5+, Y2(OH)24+, < 1. - )96+ [6, 9] 6,5 ( = 0,99), Y(OH)3 = 0,80) . % (∆lg s = 0,09), 10−5 · −1 5,5 ( = 0,94) 0,6 (∆lg s = 0,003), , [M3+], 0−14. − ( ) [1] . Ks = −lgKs, s − . 1, - . , [M(OH)3] – 25 . Ks , - .1 [3, 10]. . , , , , 1 ( 2). La(OH)3 (42−96 . %). Y(OH)3 Y(OH)2+. 158 III . .1 , Sc(OH)3 - 1 25 pKs H2O [3, 7] Sc(OH)3* 29,8 29,7 Sc(OH)3· H2O 30,7 − Sc(OH)3 32,72 33,0 * S [M(OH)3] 7,77 1,4·10 −5 1,3·10 7,07 1,6 ·10−7 1,3·10−7 −6 / 1 NaOH s / 8,05 1,1·10−4 1,0·10−4 −5 S, NaOH A 8,16 3,97 1,7 4,6·104 8,16 4,86 0,22 4,5·104 8,16 6,88 2,1·10−3 3,8·104 −6 8,16 5,66 0,034 4,3·104 7,02 3,8·10−8 3,0·10−8 8,16 7,51 4,8·10−4 3,7·104 α−ScOOH 31,6 31,5 ScO1.5* 33,4 − ScO1.5 36,6 36,3 7,00 3,0·10−11 2,3·10−11 8,16 10,6 3,7·10−7 3,7·104 Y(OH)3* 22,77 − 8,62 4,6·10−6 1,2·10−6 10,31 5,68 2,0·10−4 1,3·102 Y(OH)3 24,45 24,50 8,07 5,6·10−7 3,2·10−8 10,31 7,43 3,6·10−6 α−YO1.5** 18,47 18,1 La(OH)3* 18,98 19,19 9,93 1,4·10−3 1,3·10−3 11,05 2,89 7,3·10−3 La(OH)3 21,6 21,7 La(OH)3 · H2O 22,6 − 7,43 2,4 ·10 2,1·10 10,2 3,4·10−2 3,3·10−2 10,31 1,47 −6 5,9 8,53 1,9·10−6 2,8·10−7 11,05 6,54 1,6·10−6 2,1 * 3,1·10 11,05 5,46 1,8·10 . ** . .1 ( ( = 7,0−7,1), = 7,8−9,9). , , – ( 3+ – )3 s Sc < Y < La ( Pi 13 −5 8,86 7,4·10 −6 19 3,1·102 ,6 . .1 [7] 69 % (Sc – O) 76 % (La – O) . s (3,8 / ) α−Y2O3 [5, 7]. [6] , ). Pi , Y2O3 159 , Sc2O3, , La2O3. Y2O3 (7 · 10−6 s . 1). / , . . 1) , s s (1 · 10−6 / [5]) ScOOH Sc2O3 Y2O3 La2O3 , / ) ( . α−ScOOH (2 · 10−6 - 2 3 [2]. s( / ) 25 . La(OH)3; 2 − La(OH)3; 3 – Y(OH)3; 4 – Sc(OH)3; 5 – ScO1,5 1– n ) 15 ( ~4 , n>3 , [2]. − ( s 160 , = − lg s [1, 2], 25 ( - )3 2 3 , . )3 s . - .1, − - ( NaOH) Y(OH)3 - . La(OH)3 − - ( . , ( : 2 3). . 1) , - ~5, 7 8 [5]. , La(OH)3 Sc(OH)3 . , [1, 2], ( > 1) NaOH) 14,7 (5 . ~4 · 104 ( ) ( ( NaOH . )3 Sc > La >Y. Ks , −Ga2O3 [2], 4 5). Sc2O3 ( 5( La3+ - )4− ( c ~20 6 . 1). 1 5 . , HClO4) Y3+, – Sc < Y < La. , Sc2O3, Sc(OH)3 α−ScOOH 25 5 NaOH ( s ( . 1). 8 · 10−5, 0,6 8 / ) Sc2O3, Sc(OH)3 · H2O Sc(OH)3 (~0,1, 60 470 / ). 2+ ScOH , . ∆G298 298 ( – ) : ( )3 ( ) ⇄ 2+ ( )+2 − ( ), (2) 161 ( )3 ( ) ⇄ ( ( Sc2O3 (2) – (6) ScO1.5 ( ) + 1,5 )3 ( ) + 2 )3 ( ) ⇄ ( ( )⇄ , − )2+ + ( ( ), (3) )3 ( ), + ( )+ (4) )4− ( ). ( (5) Sc(OH)3 ( ) : ( ). 2 2 (2)–(5), (6)−(8) (9) 298 (2) (3) (4) (5) (6) (7) (8) (9) Sc(OH)3 20,0 11,4 3,86 13,7 −2,59 −7,98 −12,3 −0,30 Y(OH)3 18,6 12,9 7,47 19,5 −1,11 −9,42 −17,5 5,48 La(OH)3 16,1 10,8 5,51 18,9 −3,18 −11,9 −20,4 4,68 ScO1.5 26,6 18,0 10,5 20,3 4,02 −1,38 −5,67 6,31 YO1.5 − − − − −6,86 −15,2 −23,3 − LaO1.5 − − − − −23,5 −32,1 −40,6 − 298 . 2, [4, 7, 8, 10] - −Ga2O3 [2]). - , ( )3 Sc < Y < La. (5) Sc(OH)3 ( = 13,7, 298 : ( )3 ( ) + ( )3 ( ) + 2 ( ( )⇄ + )3 ( ) + 3 ( 162 + ( )⇄ )3 ( ) + + 2+ ( )⇄ − ) 2+( ) + ( 3+ ( )+2 ( )+3 ( )⇄ ( 2 2 ( ), (6) 2 ( ), (7) ( ), )4− ( ) (8) (9) . .2 , , - – . , , - [5, 6]. 1. ( )3 , . La(OH)3 > Y(OH)3 > Sc(OH)3 > Sc2O3. 2. ( - )3, 25 ~4 · 104 ~6 > 1, - Sc > Y > La. 3. 8,16, 10,3 11,05 Sc(OH)3, Y(OH)3 La(OH)3 . 4. , Sc(OH)3 < Y(OH)3 < La(OH)3. , - . 1. , 2. . . [ ]/ . . // . – 2009. – III . 189. − . 206−213. , . . III [ ]/ . . // 163 . 194. − . 176−182. 3. , . .C .: , 1989. – 448 . 4. , . . . . , . . , . . 5. [ . – .: , 1988–1995. – . 1. – 6. , . . . . , . . , , 2007. – 537 . 7. , . . . . , . . , . . 392 . 8. , 1981. – 488 . 9. , . . . . , . . .– 10. , . . , . . .– . − 2011. – [ .– ]/ . 4. ]/ . [ ] : , 2006. – 685 . . . , . .: . . . ]/ . . .– / . . . . / , 1983. – . – .: [ : , 1988. – 294 . [ ]/ . . , 1983. – 267 . : - [ ] / . – . 1. – .: . [ ]: . – .: , . . [ . , . . ] / - 25 , 2 3 , – Sc, Y, La. *** The influence of hydrogen index pH on the molar solubility of M2O3 solid oxides and their hydrates in aqueous alkaline and acidic media at 25 C, as well as the heterogeneous acid−base equilibria constants were calculated for stable crystalline hydroxides M(OH)3 and oxides M2O3, where M = Sc, Y, La, by the thermodynamic method, taking into account the formation of mono- and polynuclear hydroxo complexes. 164