VIII.
IV.—The Octahedral Groups.
These groups are at the turns of the spiral in Sir William Crookes' lemniscates (see [p. 28]). On the one side is carbon, with below it titanium and zirconium; on the other silicon, with germanium and tin. The characteristic form is an octahedron, rounded at the angles and a little depressed between the faces in consequence of the rounding; in fact, we did not, at first, recognize it as an octahedron, and we called it the "corded bale," the nearest likeness that struck us. The members of the group are all tetrads, and have eight funnels, opening on the eight faces of the octahedron. The first group is paramagnetic and positive; the corresponding one is diamagnetic and negative. The two groups are not closely allied in composition, though both titanium and tin have in common the five intersecting tetrahedra at their respective centres.
Carbon
(
, 5, and
, 1) gives us the fundamental octahedral form, which becomes so masked in titanium and zirconium. As before said (
), the protrusion of the arms in these suggests the old Rosicrucian symbol of the cross and rose, but they show at their ends the eight carbon funnels with their characteristic contents, and thus justify their relationship. The funnels are in pairs, one of each pair showing three "cigars," and having as its fellow a funnel in which the middle "cigar" is truncated, thus loosing one atom. Each "cigar" has a leaf-like body at its base, and in the centre of the octahedron is a globe containing four atoms, each within its own wall; these lie on the dividing lines of the faces, and each holds a pair of the funnels together. It seems as though this atom had been economically taken from the "cigar" to form a link. This will be more clearly seen when we come to separate the parts from each other. It will be noticed that the atoms in the "leaves" at the base vary in arrangement, being alternately in a line and in a triangle.
{ left 27
CARBON: One pair of funnels { right 22
{ centre 1
--
54
4 pairs of funnels of 54 atoms 216
Atomic weight 11.91
Number weight 216/18 12.00
Titanium
(
, 6, and
, 2) has a complete carbon atom distributed over the ends of its four arms, a pair of funnels with their linking atom being seen in each. Then, in each arm, comes the elaborate body shown as 3
c
, with its eighty-eight atoms. A ring of twelve ovoids (3
d
) each holding within itself fourteen atoms, distributed among three contained globes—two quartets and a sextet—is a new device for crowding in material. Lastly comes the central body (4
e
) of five intersecting tetrahedra, with a "cigar" at each of their twenty points—of which only fifteen can be shown in the diagram—and a ring of seven atoms round an eighth, that forms the minute centre of the whole. Into this elaborate body one hundred and twenty-eight atoms are built.
TITANIUM: One carbon atom 216
4 c of 88 atoms 352
12 d of 14 " 168
Central globe 128
----
Total 864
----
Atomic weight 47.74
Number weight 864/18 48.00
Zirconium
(
, 3) has exactly the same outline as titanium, the carbon atom is similarly distributed, and the central body is identical. Only in 5
c
and
d
do we find a difference on comparing them with 4
c
and
d
. The
c
ovoid in zirconium shows no less than fifteen secondary globes within the five contained in the ovoid, and these, in turn, contain altogether sixty-nine smaller spheres, with two hundred and twelve atoms within them, arranged in pairs, triplets, quartets, quintets, a sextet and septets. Finally, the ovoids of the ring are also made more elaborate, showing thirty-six atoms instead of fourteen. In this way the clever builders have piled up in zirconium no less than 1624 atoms.
ZIRCONIUM: One Carbon atom 216
4 c of 212 atoms 848
12 d of 36 " 432
Central globe 128
----
Total 1624
----
Atomic weight 89.85
Number weight 90.22
Silicon
(
, 1) is at the head of the group which corresponds to carbon on the opposite turn of the lemniscate. It has the usual eight funnels, containing four ovoids in a circle, and a truncated "cigar" but no central body of any kind. All the funnels are alike.
SILICON: 8 funnels of 65 atoms 520
Atomic weight 28.18
Number weight 520/18 28.88
Germanium
(
, 2) shows the eight funnels, containing each four segments (
, 4), within which are three ovoids and a "cigar." In this case the funnels radiate from a central globe, formed of two intersecting tetrahedra, with "cigars" at each point enclosing a four-atomed globe.
GERMANIUM: 8 funnels of 156 atoms 1248
Central globe 52
----
Total 1300
----
Atomic weight 71.93
Number weight 1300/18 72.22
Tin
(
, 3) repeats the funnel of germanium, and the central globe we met with in titanium, of five intersecting tetrahedra, carrying twenty "cigars"; the latter, however, omits the eight-atomed centre of the globe that was found in titanium, and hence has one hundred and twenty atoms therein instead of one hundred and twenty-eight. Tin, to make room for the necessary increase of atoms, adopts the system of spikes, which we met with in zinc (see
, 2); these spikes, like the funnels, radiate from the central globe, but are only six in number. The twenty-one-atomed cone at the head of the spike we have already seen in silver, and we shall again find it in iridium and platinum; the pillars are new in detail though not in principle, the contained globes yielding a series of a triplet, quintet, sextet, septet, sextet, quintet, triplet.
TIN: 8 funnels of 156 atoms 1248
6 spikes of 126 " 756
Central globe 120
----
Total 2124
----
Atomic weight 118.10
Number weight 2124/18 118.00
V.—The Bars Groups.
Here, for the first time, we find ourselves a little at issue with the accepted system of chemistry. Fluorine stands at the head of a group—called the inter-periodic—whereof the remaining members are (see Crookes' table, [p. 28]), manganese, iron, cobalt, nickel; ruthenium, rhodium, palladium; osmium, iridium, platinum. If we take all these as group V, we find that fluorine and manganese are violently forced into company with which they have hardly any points of relationship, and that they intrude into an otherwise very harmonious group of closely similar composition. Moreover, manganese reproduces the characteristic lithium "spike" and not the bars of those into whose company it is thrust, and it is thus allied with lithium, with which indeed it is almost identical. But lithium is placed by Crookes at the head of a group, the other members of which are potassium, rubidium and cæsium (the last not examined). Following these identities of composition, I think it is better to remove manganese and fluorine from their incongruous companions and place them with lithium and its allies as V a, the Spike Groups, marking, by the identity of number, similarities of arrangement which exist, and by the separation the differences of composition. It is worth while noting what Sir William Crookes, in his "Genesis of the Elements," remarks on the relations of the interperiodic group with its neighbours. He says: "These bodies are interperiodic because their atomic weights exclude them from the small periods into which the other elements fall, and because their chemical relations with some members of the neighbouring groups show that they are probably interperiodic in the sense of being in transition stages."
Group V in every case shows fourteen bars radiating from a centre as shown in iron, [Plate IV], 1. While the form remains unchanged throughout, the increase of weight is gained by adding to the number of atoms contained in a bar. The group is made up, not of single chemical elements, as in all other cases, but of sub-groups, each containing three elements, and the relations within each sub-group are very close; moreover the weights only differ by two atoms per bar, making a weight difference of twenty-eight in the whole. Thus we have per bar:—
Iron 72 Palladium 136
Nickel 74 Osmium 245
Cobalt 76 Iridium 247
Ruthenium 132 Platinum A 249
Rhodium 134 Platinum B 257
It will be noticed ([Plate XVII], 3, 4, 5,) that each bar has two sections, and that the three lower sections in iron, cobalt and nickel are identical; in the upper sections, iron has a cone of twenty-eight atoms, while cobalt and nickel have each three ovoids, and of these the middle ones alone differ, and that only in their upper globes, this globe being four-atomed in cobalt and six-atomed in nickel.
The long ovoids within each bar revolve round the central axis of the bar, remaining parallel with it, while each spins on its own axis; the iron cone spins round as though impaled on the axis.
Iron
(Plate
, 1, and
, 3):
14 bars of 72 atoms 1008
Atomic weight 55.47
Number weight 1008/18 56.00
Cobalt
(
, 4):
14 bars of 74 atoms 1036
Atomic weight 57.70
Number weight 1036/18 57.55
Nickel
(
, 4):
14 bars of 76 atoms 1064
Atomic weight 58.30
Number weight 1064/18 59.11
(The weight of cobalt, as given in Erdmann's Lehrbuch, is 58.55, but Messrs. Parker and Sexton, in Nature, August 1, 1907, give the weight, as the result of their experiments, as 57.7.)
The next sub-group, ruthenium, rhodium, and palladium, has nothing to detain us. It will be observed that each bar contains eight segments, instead of the six of cobalt and nickel; that ruthenium and palladium have the same number of atoms in their upper ovoids, although in ruthenium a triplet and quartet represent the septet of palladium; and that in ruthenium and rhodium the lower ovoids are identical, though one has the order: sixteen, fourteen, sixteen, fourteen; and the other: fourteen, sixteen, fourteen, sixteen. One constantly asks oneself: What is the significance of these minute changes? Further investigators will probably discover the answer.
Ruthenium
(
, 1):
14 bars of 132 atoms 1848
Atomic weight 100.91
Number weight 1848/18 102.66
Rhodium
(
, 2):
14 bars of 134 atoms 1876
Atomic weight 102.23
Number weight 1876/18 104.22
Palladium
(
, 3):
14 bars of 136 atoms 1904
Atomic weight 105.74
Number weight 1904/18 105.77
The third sub-group, osmium, iridium and platinum, is, of course, more complicated in its composition, but its builders succeed in preserving the bar form, gaining the necessary increase by a multiplication of contained spheres within the ovoids. Osmium has one peculiarity: the ovoid marked a ([XVIII], 4) takes the place of axis in the upper half of the bar, and the three ovoids, marked b, revolve round it. In the lower half, the four ovoids, c, revolve round the central axis. In platinum, we have marked two forms as platinum A and platinum B, the latter having two four-atomed spheres ([XVIII], 6 b) in the place of the two triplets marked a. It may well be that what we have called platinum B is not a variety of platinum, but a new element, the addition of two atoms in a bar being exactly that which separates the other elements within each of the sub-groups. It will be noticed that the four lower sections of the bars are identical in all the members of this sub-group, each ovoid containing thirty atoms. The upper ring of ovoids in iridium and platinum A are also identical, but for the substitution, in platinum A, of a quartet for a triplet in the second and third ovoids; their cones are identical, containing twenty-one atoms, like those of silver and tin.
Osmium
(
, 4):
14 bars of 245 atoms 3430
Atomic weight 189.55
Number weight 3430/18 190.55
Iridium
(
, 5):
14 bars of 247 atoms 3458
Atomic weight 191.11
Number weight 3458/18 192.11
Platinum A
(
, 6
a
):
14 bars of 249 atoms 3486
Atomic weight 193.66
Number weight 3486/18 193.34
Platinum B
(
, 6
b
):
14 bars of 251 atoms 3514
Atomic weight ------
Number weight 3514/18 195.22
V a.—The Spike Groups.
I place within this group lithium, potassium, rubidium, fluorine, and manganese, because of their similarity in internal composition. Manganese has fourteen spikes, arranged as in the iron group, but radiating from a central globe. Potassium has nine, rubidium has sixteen, in both cases radiating from a central globe. Lithium ([Plate IV], 2) and fluorine ([Plate IV], 3) are the two types which dominate the group, lithium supplying the spike which is reproduced in all of them, and fluorine the "nitrogen balloon" which appears in all save lithium. It will be seen that the natural affinities are strongly marked. They are all monads and paramagnetic; lithium, potassium and rubidium are positive, while fluorine and manganese are negative. We seem thus to have a pair, corresponding with each other, as in other cases, and the interperiodic group is left interperiodic and congruous within itself.
Lithium
(
, 2 and
, 1) is a striking and beautiful form, with its upright cone, or spike, its eight radiating petals (
x
) at the base of the cone, and the plate-like support in the centre of which is a globe, on which the spike rests. The spike revolves swiftly on its axis, carrying the petals with it; the plate revolves equally swiftly in the opposite direction. Within the spike are two globes and a long ovoid; the spheres within the globe revolve as a cross; within the ovoid are four spheres containing atoms arranged on tetrahedra, and a central sphere with an axis of three atoms surrounded by a spinning wheel of six.
LITHIUM: Spike of 63 atoms 63
8 petals of 6 atoms 48
Central globe of 16 atoms 16
----
Total 127
----
Atomic weight 6.98
Number weight 127/18 7.05
Potassium
(
, 2) consists of nine radiating lithium spikes, but has not petals; its central globe contains one hundred and thirty-four atoms, consisting of the "nitrogen balloon," encircled by six four-atomed spheres.
POTASSIUM: 9 bars of 63 atoms 567
Central globe 134
----
Total 701
----
Atomic weight 38.94
Number weight 701/18 38.85
(The weight, as determined by Richards [Nature, July 18, 1907] is 39.114.)
Rubidium
: (
, 3) adds an ovoid, containing three spheres—two triplets and a sextet—to the lithium spike, of which it has sixteen, and its central globe is composed of three "balloons."
RUBIDIUM: 16 spikes of 75 atoms 1200
Central globe 330
----
Total 1530
----
Atomic weight 84.85
Number weight 1530/18 85.00
The corresponding negative group consists only of fluorine and manganese, so far as our investigations have gone.
Fluorine
(
, 3, and
, 1) is a most peculiar looking object like a projectile, and gives one the impression of being ready to shoot off on the smallest provocation. The eight spikes, reversed funnels, coming to a point, are probably responsible for this warlike appearance. The remainder of the body is occupied by two "balloons."
FLUORINE: 8 spikes of 15 atoms 120
2 balloons 220
----
Total 340
----
Atomic weight 18.90
Number weight 340/18 18.88
Manganese
(
, 2) has fourteen spikes radiating from a central "balloon."
MANGANESE: 14 spikes of 63 atoms 882
Central balloon 110
----
Total 992
----
Atomic weight 54.57
Number weight 992/18 55.11