CMDFCrystalMakerW 9.2.9f1 REND_2?^> ? ? @? > ? @? > ? Y?Q> #< DCUE > fff?DOPC ? ? ?dprx ? ? ? ?fff? > PRSP HBMODLBSSRL>>BRAD > ?BDEF SURF ? ? ? ? UCEL ? AXES LABLTahoma LABX @ABACK BAKG ? BCOL CELLfff@fff@Q@ B B BCFORAs 1.00 Ni 1.00VIEWfD}F=4f7?Y3@E:j%>u@k4a@ӯ/=?RAN7>@?@$>ed@SCAL@ A6QA@SCA8n BSYMMP 63/m m c P*?> @? SYSTDENSECVOL8`BAUN7 sA ? X iN ? A >*? > SPH7 sA? ! a iN333? sA? sA? BON7 iNsA ff&@ ATO7 *?> ? *?? ? UU?? ? *@? ? j@? ? UU@? ? *?UU@ ? UU?UU@ ? *@UU@ ? j@UU@ ? UU@UU@ ? *?UUU@ ? ! UU?UUU@ ? # *@UUU@ ? % j@UUU@ ? ' UU@UUU@ ? ) *?@ ? + UU?@ ? - *@@ ? / j@@ ? ! 1 UU@@ ? ! 3 *?@ ? 5 UU?@ ? 7 *@@ ? 9 j@@ ? ; UU@@ ? ! G *?? ? 8 9 H ? ? ? 8 I UU?? ? 8 9 : ; J @ ? ? : K *@? ? : ; < = L @@ ? ? < M j@? ? < = > ? N @ ? ? > O UU@? ? > ? Q *?UU@ ? B C R ? @ ? 8 B S UU?UU@ ? 8 9 B C D E T @ @ ? 8 : D U *@UU@ ? : ; D E F G V @@ @ ? : < F W j@UU@ ? < = F G H I X @ @ ? < > H Y UU@UU@ ? > ? H I [ *?UUU@ ? L M \ ? @@ ? B L ] UU?UUU@ ? B C L M N O ^ @ @@ ? B D N _ *@UUU@ ? D E N O P Q ` @@ @@ ? D F P a j@UUU@ ? F G P Q R S b @ @@ ? F H R c UU@UUU@ ? H I R S e *?@ ? V W f ? @ ? L V g UU?@ ? L M V W X Y h @ @ ? L N X i *@@ ? N O X Y Z [ j @@ @ ? N P Z k j@@ ? P Q Z [ \ ] l @ @ ? ! P R \ m UU@@ ? R S \ ] o *?@ ? p ? @ ? V q UU?@ ? V W r @ @ ? V X s *@@ ? X Y t @@ @ ? X Z u j@@ ? Z [ v @ @ ? ! Z \ w UU@@ ? \ ] *?? @ t u ? ? @ 9 t UU?? @ t u v w @ ? @ ; v *@? @ v w x y @@ ? @ = x j@? @ x y z { @ ? @ ? z UU@? @ z { *?UU@ @ ~ ? @ @ 9 C t ~ UU?UU@ @ t u ~ @ @ @ 9 ; E t v *@UU@ @ v w @@ @ @ ; = G v x j@UU@ @ x y @ @ @ = ? I x z UU@UU@ @ z { *?UUU@ @ ? @@ @ C M ~ UU?UUU@ @ ~ @ @@ @ C E O ~ *@UUU@ @ @@ @@ @ E G Q j@UUU@ @ @ @@ @ G I S UU@UUU@ @ *?@ @ ? @ @ M W UU?@ @ @ @ @ M O Y *@@ @ @@ @ @ O Q [ j@@ @ @ @ @ Q S ] UU@@ @ *?@ @ ? @ @ W UU?@ @ @ @ @ W Y *@@ @ @@ @ @ Y [ j@@ @ @ @ @ [ ] UU@@ @ *?? `@ ? ? @@ u UU?? `@ @ ? @@ w *@? `@ @@ ? @@ y j@? `@ @ ? @@ { UU@? `@ *?UU@ `@ ? @ @@ u UU?UU@ `@ @ @ @@ u w *@UU@ `@ @@ @ @@ w y j@UU@ `@ @ @ @@ y { UU@UU@ `@ *?UUU@ `@ ? @@ @@ UU?UUU@ `@ @ @@ @@ *@UUU@ `@ @@ @@ @@ j@UUU@ `@ @ @@ @@ UU@UUU@ `@ *?@ `@ ? @ @@ UU?@ `@ @ @ @@ *@@ `@ @@ @ @@ j@@ `@ @ @ @@ UU@@ `@ *?@ `@ ? @ @@ UU?@ `@ @ @ @@ *@@ `@ @@ @ @@ j@@ `@ @ @ @@ UU@@ `@ >*? > >*? @? ?UU? @? H T R UU@UU? @? J V T UUU@UU? @? L X V @UU? @? N X ?*@ @? R ^ \ ! UU@*@ @? T ` ^ # UUU@*@ @? V b ` % @*@ @? X b ' ?j@ @? \ ! h f + UU@j@ @? ^ # ! j h - UUU@j@ @? ` % # l j / @j@ @? b ' % l 1 ?UU@ @? f + ) r p 5 UU@UU@ @? h - + t r 7 UUU@UU@ @? j / - v t 9 ! @UU@ @? l 1 / v ; 8 ?UU? ? H I G T R S 9 ?UU? ? I G S : UU@UU? ? J K I V T U ; UU@UU? ? K I U < UUU@UU? ? L M K X V W = UUU@UU? ? M K W > @UU? ? N O M X Y ? @UU? ? O M Y B ?*@ ? R S Q ^ \ ] C ?*@ ? S Q ] D UU@*@ ? T U S ` ^ _ E UU@*@ ? U S _ F UUU@*@ ? V W U b ` a G UUU@*@ ? W U a H @*@ ? X Y W b c I @*@ ? Y W c L ?j@ ? \ ] [ h f g M ?j@ ? ] [ g N UU@j@ ? ^ _ ] j h i O UU@j@ ? _ ] i P UUU@j@ ? ` a _ l j k Q UUU@j@ ? a _ k R @j@ ? b c a l m S @j@ ? c a m V ?UU@ ? f g e r p q W ?UU@ ? g e q X UU@UU@ ? h i g t r s Y UU@UU@ ? i g s Z UUU@UU@ ? j k i v t u [ UUU@UU@ ? k i u \ @UU@ ? l m k v w ] @UU@ ? m k w t ?UU? @ u ?UU? 0@ v UU@UU? @ w UU@UU? 0@ x UUU@UU? @ y UUU@UU? 0@ z @UU? @ { @UU? 0@ ~ ?*@ @ ?*@ 0@ UU@*@ @ UU@*@ 0@ UUU@*@ @ UUU@*@ 0@ @*@ @ @*@ 0@ ?j@ @ ?j@ 0@ UU@j@ @ UU@j@ 0@ UUU@j@ @ UUU@j@ 0@ @j@ @ @j@ 0@ ?UU@ @ ?UU@ 0@ UU@UU@ @ UU@UU@ 0@ UUU@UU@ @ UUU@UU@ 0@ @UU@ @ @UU@ 0@ ?UU? P@ UU@UU? P@ UUU@UU? P@ @UU? P@ ?*@ P@ UU@*@ P@ UUU@*@ P@ @*@ P@ ?j@ P@ UU@j@ P@ UUU@j@ P@ @j@ P@ ?UU@ P@ UU@UU@ P@ UUU@UU@ P@ @UU@ P@ POL7u S 8 9 E D 8 9 C B 8 D B 9 E C E D B C T 8 D 8 : D : D 8 : U : F G ; : ; E D : F D G ; E G F D E V F : F < F : < : < W < H I = < = G F < H F I = G I H F G X H < H > H < > < > ] B C O N B C M L B N L C O M O N L M ^ B N B D N D N B D _ Q P D E Q E O Q P N O D E O N D P N ` D P D F P F P D F a F R S G F G Q P F R P S G Q S R P Q b F R F H R H R F H g L M Y X L M W V L X V M Y W Y X V W h L X L N X N X L N i [ Z N O [ O Y [ Z X Y N O Y X N Z X j N Z N P Z P Z N P k ] \ P Q ] Q [ ] \ Z [ P Q [ Z P \ Z l P \ ! ! P R \ ! R \ P R t u t u ~ t ~ u ~ 9 t E 9 E ; 9 t v ; E ; v t v v w v w v w v ; G G = x v x ; G = ; v x = x y y x y x x = I I ? z x z = I ? = x z ? ~ ~ ~ C ~ O C O E C ~ E O E ~ E Q E Q G E G Q G G S S I G S I G I M Y M Y O M O Y O O [ [ Q O [ Q O Q Q ] Q ] S Q S ] S u u w u w w w w y w y y y { y { y { T T R T H T H R R H H R V V T T V J V J T J J T X V X X L V X L V L V L ^ ! \ ^ ! ^ R \ ^ R ! \ ! R \ R ` # ^ ` # ` T ^ ` T # ^ # T ^ T b % ` b % b V ` b V % ` % V ` V h + f h + ! h \ f h \ ! + f + ! \ f \ ! j - h j - # j ^ h j ^ # ! - h ! - # ! ^ h ! ^ # # / j # / % # ` j # ` % l / j l / % l ` j l ` % r 5 p r 5 + r f p r f + 5 ) p 5 ) + ) f p ) f + t 7 r t 7 - t h r t h - + 7 r + 7 - + h r + h - 9 v t 9 v / 9 - t 9 - / v j t v j / - j t - j / 8 S T R S T I S G R S G I H T R H T I H G R H G I 9 S S I I S G S G I G G I : U V T U V K U I T U I K J V T J V K J I T J I K ; K U U K I I K U I U I K < L X V L X M L K V L K M W X V W X M W K V W K M = K W K W M K K M W W M M B ] ^ \ ] ^ S ] Q \ ] Q S R ^ \ R ^ S R Q \ R Q S C ] ] S S ] Q ] Q S Q Q S D _ ` ^ _ ` U _ S ^ _ S U T ` ^ T ` U T S ^ T S U E _ _ U U _ S _ S U S S U F a b ` a b W a U ` a U W V b ` V b W V U ` V U W G a a W a U a U W W U U W L g h ] g h f g [ ] g [ f \ h ] \ h f \ [ ] \ [ f M g g ] ] [ g [ g ] [ [ ] N i j h i j _ i ] h i ] _ ^ j h ^ j _ ^ ] h ^ ] _ O i i _ i ] i ] _ _ ] ] _ P k _ j k _ a k l j k l a ` _ j ` _ a ` l j ` l a Q _ k _ k a _ _ a k k a a V q r p q r g q e p q e g f r p f r g f e p f e g W q q g q e q e g g e e g X s t r s t i s g r s g i h t r h t i h g r h g i Y s s i i s g s g i g g i Z u i t u i k u v t u v k j i t j i k j v t j v k [ u u k u i u i k k i i k t u v w x y ~ GRID STER @ TBXU ?>>=L>>NOTRo {\rtf1\ansi\ansicpg1252 {\fonttbl\f0\fswiss Geneva;} {\colortbl\red0\green0\blue0;} \f0 \cf0 \fs24 Nickel Arsenide structure (NiAs).\par \par The As ("X") atoms are arranged in an hexagonally close-packed array. The Ni ("A") atoms occupy the octahedral interstices. Thus, each Ni atom is surrounded by six As atoms, arranged at the corners of an octahedron. Conversely, each As atom is surrounded by six Ni atoms, arranged at the corners of a trigonal prism.\par \par [[Viewing hint: in Polyhedral mode you can see the NiAs6 octahedra. Using the Model Options dialog and the Polyhedra panel, you could instead opt to view AsNi6 polyhedra]]\par \par Note that the NiAs6 octahedra share faces. According to Pauling's third rule, such face-sharing decreases the stability of an ionic structure. This is why purely ionic AX compounds tend to adopt the NaCl structure.\par \par The NiAs structure type is generally appropriate for AX compounds in which the bonding is appreciably metallic.\par \par Spacegroup: P 6.3/m m c (note that the origin is displaced by 1/3, 2/3, 1/4 - so that the 6.3 axis passes vertically through the Ni atoms).} NOTU N i c k e l A r s e n i d e s t r u c t u r e ( N i A s ) . T h e A s ( " X " ) a t o m s a r e a r r a n g e d i n a n h e x a g o n a l l y c l o s e - p a c k e d a r r a y . T h e N i ( " A " ) a t o m s o c c u p y t h e o c t a h e d r a l i n t e r s t i c e s . T h u s , e a c h N i a t o m i s s u r r o u n d e d b y s i x A s a t o m s , a r r a n g e d a t t h e c o r n e r s o f a n o c t a h e d r o n . C o n v e r s e l y , e a c h A s a t o m i s s u r r o u n d e d b y s i x N i a t o m s , a r r a n g e d a t t h e c o r n e r s o f a t r i g o n a l p r i s m . [ [ V i e w i n g h i n t : i n P o l y h e d r a l m o d e y o u c a n s e e t h e N i A s 6 o c t a h e d r a . U s i n g t h e M o d e l O p t i o n s d i a l o g a n d t h e P o l y h e d r a p a n e l , y o u c o u l d i n s t e a d o p t t o v i e w A s N i 6 p o l y h e d r a ] ] N o t e t h a t t h e N i A s 6 o c t a h e d r a s h a r e f a c e s . A c c o r d i n g t o P a u l i n g ' s t h i r d r u l e , s u c h f a c e - s h a r i n g d e c r e a s e s t h e s t a b i l i t y o f a n i o n i c s t r u c t u r e . T h i s i s w h y p u r e l y i o n i c A X c o m p o u n d s t e n d t o a d o p t t h e N a C l s t r u c t u r e . T h e N i A s s t r u c t u r e t y p e i s g e n e r a l l y a p p r o p r i a t e f o r A X c o m p o u n d s i n w h i c h t h e b o n d i n g i s a p p r e c i a b l y m e t a l l i c . S p a c e g r o u p : P 6 . 3 / m m c ( n o t e t h a t t h e o r i g i n i s d i s p l a c e d b y 1 / 3 , 2 / 3 , 1 / 4 - s o t h a t t h e 6 . 3 a x i s p a s s e s v e r t i c a l l y t h r o u g h t h e N i a t o m s ) . PRVWJPEG " JFIF ` ` C $ &%# #"(-90(*6+"#2D26;=@@@&0FKE>J9?@= C =)#)================================================== " } !1AQa"q2#BR$3br %&'()*456789:CDEFGHIJSTUVWXYZcdefghijstuvwxyz w !1AQaq"2B #3Rbr $4%&'()*56789:CDEFGHIJSTUVWXYZcdefghijstuvwxyz ? ZZ(((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((B@'ީvsv