An exhibition of the sixth element.
第六元素の展覧会
Welcome to tanso.center — a quiet hall dedicated to the science, structure, and stories of carbon. The visitor is invited to walk slowly between exhibits, where each panel rises from the surface to present a single facet of the element that builds the world.
The collection is organized by allotrope: distinct arrangements of the same atom that produce diamonds, pencil leads, soccer-ball molecules, atom-thick sheets, and impossibly slender tubes. Begin at any exhibit. The hall does not close.
A lattice that refuses to bend.
屈しない格子
In diamond, each carbon atom binds to four others in a perfect tetrahedron. The bonds are short, equal, and uncompromisingly directional — the resulting three-dimensional network leaves no room for compression, no slip plane for shear. Hardness is not a feeling; it is geometry made rigid.
- Bonding
- sp³ tetrahedral, σ only
- Density
- 3.515 g · cm⁻³
- Mohs hardness
- 10.0 (reference)
- Refractive index
- 2.418 at 589 nm
- Thermal cond.
- 2200 W · m⁻¹ · K⁻¹
Layers that prefer to slide.
滑りたがる層
Graphite is carbon arranged into hexagonal sheets — strong rings of three-bonded atoms — that stack in parallel and hold one another loosely. The rigidity of the sheet and the gentleness between sheets together produce a material that conducts, lubricates, and writes on paper.
Each sheet is, in itself, a piece of graphene. Graphite is therefore an exhibit of cooperation: countless single layers behaving as one specimen.
- Bonding
- sp², in-plane σ + delocalised π
- Interlayer spacing
- 3.354 Å
- Density
- 2.267 g · cm⁻³
- Mohs hardness
- 1.0 — 2.0
- In-plane cond.
- ≈ 4 × 10⁵ S · m⁻¹
A cage made of corners.
角でできた籠
In 1985, three chemists vaporising graphite found a stable, closed sphere of sixty carbon atoms — the same geometry as a football. They named it after the architect of the geodesic dome. Each pentagon enforces curvature; each hexagon stabilises the surface. The result is a hollow cage that sits cleanly inside a single molecule.
- Formula
- C₆₀ (truncated icosahedron)
- Faces
- 12 pentagons · 20 hexagons
- Cage diameter
- ≈ 7.1 Å
- Molar mass
- 720.66 g · mol⁻¹
- Discovered
- 1985 · Kroto, Curl, Smalley
A single sheet, one atom thick.
原子一層の薄板
Pull one layer from a stack of graphite and you isolate a two-dimensional crystal: hexagons of carbon extending without interruption. Electrons traverse it as if they had no mass; the sheet bears more tensile load than steel for its weight. The exhibit is therefore a study in flatness — the thinnest material that still feels like a material.
- Thickness
- ≈ 0.34 nm (one atom)
- Tensile strength
- 130 GPa
- Young's modulus
- 1.0 TPa
- Electron mobility
- ≈ 2 × 10⁵ cm² · V⁻¹ · s⁻¹
- First isolated
- 2004 · Geim, Novoselov
A sheet rolled until it closes.
巻かれて閉じる薄板
Take a sheet of graphene and roll it into a tube; the way you roll it — the chiral angle — decides whether the tube conducts as a metal or behaves as a semiconductor. The exhibit therefore presents one geometry that, with a small twist, reads as two materials. The same atoms, organised differently, do different work.
- Diameter
- 0.4 — 50 nm typical
- Length
- up to 0.5 m demonstrated
- Tensile strength
- ≈ 100 GPa
- Density
- 1.3 — 1.4 g · cm⁻³
- Conduction
- metallic or semiconducting · by chirality
The hall remains open.
館は開いたまま
Carbon is a small atom. It has only six electrons, four of them available for bonding. From this modest specification arrives diamond, graphite, fullerene, graphene, nanotube — and the chemistry of every living thing. The exhibits in this hall show only the inorganic geometry; the organic galleries occupy a building of their own.
The visitor is welcome to return. The lights will be on.